{"id":9168,"date":"2026-10-16T20:13:11","date_gmt":"2026-10-16T20:13:11","guid":{"rendered":"https:\/\/www.warmy.io\/blog\/?p=9168"},"modified":"2026-11-01T20:39:20","modified_gmt":"2026-11-01T20:39:20","slug":"smtp-ports-explained-25-465-587","status":"publish","type":"post","link":"https:\/\/www.warmy.io\/blog\/smtp-ports-explained-25-465-587\/","title":{"rendered":"SMTP Ports Explained: 25, 465, 587, and Which One to Use"},"content":{"rendered":"\n<p><strong>Short answer:<\/strong> to send from an app, CRM, or email client, use SMTP port 587 with STARTTLS, or 465 with implicit TLS if your provider asks for it. Port 25 is for server-to-server relay, and 2525 is a fallback when a network blocks the others. An email client hands outgoing mail to a provider for delivery. Mail servers then relay it toward the recipient over their own connections. <a title=\"RFC 6409 Message Submission and SMTP port 587 standard\" href=\"https:\/\/www.rfc-editor.org\/info\/rfc6409\/\" target=\"_blank\" rel=\"nofollow noopener noreferrer\">RFC 6409<\/a> separates these roles. Port 587 is reserved for submission. Server-to-server relay uses port 25. Port 465 supports submission with implicit TLS; some providers also offer 2525.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"683\" src=\"https:\/\/www.warmy.io\/blog\/wp-content\/uploads\/2026\/11\/smtp-ports-25-465-587-alternative-1024x683.jpg\" alt=\"SMTP server illustration comparing port 25 for server relay, port 465 for implicit TLS email submission and port 587 for STARTTLS submission\" class=\"wp-image-9163\" title=\"\" srcset=\"https:\/\/www.warmy.io\/blog\/wp-content\/uploads\/2026\/11\/smtp-ports-25-465-587-alternative-1024x683.jpg 1024w, https:\/\/www.warmy.io\/blog\/wp-content\/uploads\/2026\/11\/smtp-ports-25-465-587-alternative-300x200.jpg 300w, https:\/\/www.warmy.io\/blog\/wp-content\/uploads\/2026\/11\/smtp-ports-25-465-587-alternative-768x512.jpg 768w, https:\/\/www.warmy.io\/blog\/wp-content\/uploads\/2026\/11\/smtp-ports-25-465-587-alternative.jpg 1536w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p>Choose the port for SMTP submission together with the encryption mode your provider specifies for that email account. For a closer look at what happens during the connection, <a title=\"How SMTP works and how an SMTP server handles email delivery\" href=\"https:\/\/www.warmy.io\/blog\/what-is-smtp-and-how-does-the-smtp-server-work\/\" target=\"_blank\" rel=\"noopener noreferrer\">read our full breakdown of how SMTP works<\/a>.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Key Takeaways<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Don&#8217;t use port 25 for apps or email clients: it is the server-to-server relay port, and many networks block it.<\/li>\n\n\n\n<li>Port 587 is the place to start: use it with STARTTLS. It is the registered Message Submission port and the default most providers document.<\/li>\n\n\n\n<li>Use 465 when your provider specifies implicit TLS. It isn&#8217;t deprecated: <a title=\"RFC 8314 SMTP port 465 implicit TLS submission standard\" href=\"https:\/\/www.rfc-editor.org\/rfc\/rfc8314.html\" target=\"_blank\" rel=\"nofollow noopener noreferrer\">RFC 8314<\/a> (2018) registered it for submission over implicit TLS.<\/li>\n\n\n\n<li>Try port 2525 only as a fallback, when your network blocks the usual ports. It is supported by providers including <a href=\"https:\/\/www.warmy.io\/esp\/mailgun\/\" target=\"_blank\" rel=\"noreferrer noopener\">Mailgun<\/a> and <a href=\"https:\/\/www.warmy.io\/esp\/sendgrid\/\" target=\"_blank\" rel=\"noreferrer noopener\">SendGrid<\/a>.<\/li>\n\n\n\n<li>The SMTP email port determines how your app connects to the submission service. A wrong port can stop submission. But the number itself does not determine inbox or spam placement.<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Port 25: The Original SMTP Port (and Why You Shouldn&#8217;t Use It)<\/h2>\n\n\n\n<p>Port 25 is the original SMTP port, in use since SMTP was first defined in RFC 821 in 1982. It is still used by mail servers to deliver messages to the servers responsible for recipient domains. Early mail servers accepted messages from almost anyone; once spammers abused those open relays, networks started restricting port 25, and a separate submission port appeared in RFC 2476 in 1998. RFC 6409 separates it from relay traffic and reserves port 587 for messages submitted by applications and email clients.<\/p>\n\n\n\n<figure class=\"wp-block-image\"><img decoding=\"async\" src=\"https:\/\/www.warmy.io\/blog\/wp-content\/uploads\/2026\/11\/smtp-port-25-relay-vs-submission.jpg\" alt=\"Diagram showing an email app submitting messages through SMTP ports 587 or 465 and mail servers relaying messages through port 25\" title=\"SMTP Port 25 vs Ports 587 and 465: Relay and Submission\"\/><\/figure>\n\n\n\n<p>For a CRM or website sending through an authenticated provider, port 25 is usually the wrong default. ISP port blocking is another reason client setups fail on 25. <a title=\"M3AAWG SMTP port 25 blocking recommendations for email networks\" href=\"https:\/\/www.m3aawg.org\/blog\/Port25DocumentRefresh\" target=\"_blank\" rel=\"nofollow noopener noreferrer\">M3AAWG recommends<\/a> blocking access to port 25 from all hosts except those explicitly permitted to operate as SMTP relays. <a title=\"Amazon EC2 outbound SMTP port 25 restriction documentation\" href=\"https:\/\/docs.aws.amazon.com\/AWSEC2\/latest\/UserGuide\/ec2-resource-limits.html\" target=\"_blank\" rel=\"nofollow noopener noreferrer\">Amazon EC2<\/a> likewise blocks outbound port 25 to public IPv4 and IPv6 addresses by default, although customers can request removal of the restriction.<\/p>\n\n\n\n<p>Port 25 can also carry encrypted traffic. <a title=\"RFC 3207 STARTTLS extension for SMTP encryption\" href=\"https:\/\/www.rfc-editor.org\/info\/rfc3207\/\" target=\"_blank\" rel=\"nofollow noopener noreferrer\">RFC 3207<\/a> defines the STARTTLS extension used to upgrade an SMTP connection to TLS. The reason to avoid 25 for ordinary client submission is its role and common network restrictions, not an inability to encrypt mail.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Port 587: The Modern Standard<\/h2>\n\n\n\n<p><a title=\"IANA SMTP port 587 Message Submission registration\" href=\"https:\/\/www.iana.org\/assignments\/service-names-port-numbers\" target=\"_blank\" rel=\"nofollow noopener noreferrer\">Port 587<\/a> is registered for Message Submission, as defined by RFC 6409. Through this dedicated service, providers can authenticate a client and apply their sending policies before accepting its messages for delivery.<\/p>\n\n\n\n<p>STARTTLS is the usual way to <a title=\"SMTP connection encryption with STARTTLS and secure email delivery\" href=\"https:\/\/www.warmy.io\/blog\/smtp-connection-encryption-the-key-to-secure-reliable-email-delivery\/\" target=\"_blank\" rel=\"noopener noreferrer\">secure an SMTP connection<\/a> on port 587. After opening an ordinary SMTP session, the client checks whether the server advertises STARTTLS and requests an upgrade. RFC 3207 defines how this SMTP extension upgrades an initially unencrypted connection.<\/p>\n\n\n\n<p>Encryption does not replace account authentication. The submission service verifies who is sending through <a title=\"SMTP AUTH mechanisms for secure authenticated email sending\" href=\"https:\/\/www.warmy.io\/blog\/smtp-auth-mechanisms-explained-choosing-the-right-authentication-for-secure-email-sending\/\" target=\"_blank\" rel=\"noopener noreferrer\">SMTP AUTH<\/a>, the extension defined in <a title=\"RFC 4954 SMTP AUTH email authentication extension\" href=\"https:\/\/www.rfc-editor.org\/info\/rfc4954\/\" target=\"_blank\" rel=\"nofollow noopener noreferrer\">RFC 4954<\/a>.<\/p>\n\n\n\n<p><a title=\"Outlook SMTP port 587 STARTTLS settings\" href=\"https:\/\/support.microsoft.com\/en-us\/outlook\/pop-imap-and-smtp-settings-for-outlook-com\" target=\"_blank\" rel=\"nofollow noopener noreferrer\">Outlook.com<\/a> specifies port 587 with STARTTLS. Microsoft is also phasing out Basic authentication for SMTP AUTH in Exchange Online, so new setups should plan on OAuth. With Basic auth turned off, the server replies <code>550 5.7.30 Basic authentication is not supported for Client Submission<\/code> even when the port is correct.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Port 465: Deprecated or Not? Setting the Record Straight<\/h2>\n\n\n\n<p>Port 465 is a current standard for secure email submission. Port 465 briefly held the registration <code>smtps<\/code>, which was later revoked. Providers kept using it anyway. In 2018, <a title=\"RFC 8314 SMTP port 465 implicit TLS email submission\" href=\"https:\/\/www.rfc-editor.org\/rfc\/rfc8314.html\" target=\"_blank\" rel=\"nofollow noopener noreferrer\">RFC 8314<\/a> formally registered TCP 465 as <code>submissions<\/code> for Message Submission over TLS.<\/p>\n\n\n\n<p>On port 465, the TLS handshake begins as soon as the TCP connection is established, before any SMTP protocol data is exchanged. This is implicit TLS.<\/p>\n\n\n\n<figure class=\"wp-block-image\"><img decoding=\"async\" src=\"https:\/\/www.warmy.io\/blog\/wp-content\/uploads\/2026\/11\/smtp-starttls-587-vs-implicit-tls-465.jpg\" alt=\"Diagram comparing SMTP port 587, which upgrades the connection using STARTTLS, with port 465, which establishes TLS before SMTP communication begins.\" title=\"SMTP Port 587 STARTTLS vs Port 465 Implicit TLS\"\/><\/figure>\n\n\n\n<p>Correctly implemented STARTTLS on 587 and implicit TLS on 465 provide comparable security, according to RFC 8314. Both ends must require successful TLS negotiation before submission. The RFC nevertheless favors implicit TLS, which establishes encryption at the start instead of upgrading an existing connection.<\/p>\n\n\n\n<p><a title=\"RFC 8997 TLS 1.2 minimum recommendation for email submission\" href=\"https:\/\/www.rfc-editor.org\/rfc\/rfc8997.html\" target=\"_blank\" rel=\"nofollow noopener noreferrer\">RFC 8997<\/a> later updated RFC 8314 so that the minimum recommended TLS version for email submission and access is TLS 1.2.<\/p>\n\n\n\n<p>Use port 465 when your provider documents implicit TLS on that port, even if an older setup guide calls the port deprecated.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Port 2525: The Unofficial Fallback<\/h2>\n\n\n\n<p>Some providers, including Mailgun and SendGrid, offer port 2525 as an alternative SMTP endpoint. It has no standard SMTP submission role. In IANA&#8217;s registry, TCP 2525 belongs to a different service called <code>ms-v-worlds<\/code>.<\/p>\n\n\n\n<p>If your network blocks the usual submission port, 2525 may let the application connect without changing providers. Mailgun supports STARTTLS on this port.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">SMTP Ports vs. IMAP\/POP3 Ports: Don&#8217;t Confuse Sending and Receiving<\/h2>\n\n\n\n<p>SMTP submits outgoing mail and relays it between servers; IMAP and POP3 give clients access to messages already in a mailbox. Changing an IMAP4 port will not correct an SMTP mail port setting. The table below shows the standard ports and encryption model for each service.<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>Protocol\/service<\/th><th>Port<\/th><th>Main role<\/th><th>Connection model<\/th><\/tr><\/thead><tbody><tr><td>SMTP<\/td><td>25<\/td><td>Server-to-server relay<\/td><td>STARTTLS possible<\/td><\/tr><tr><td>SMTP submission<\/td><td>587<\/td><td>Client\/app sending<\/td><td>STARTTLS<\/td><\/tr><tr><td>SMTP submissions<\/td><td>465<\/td><td>Client\/app sending<\/td><td>Implicit TLS<\/td><\/tr><tr><td>SMTP alternative<\/td><td>2525<\/td><td>Provider-specific fallback<\/td><td>Provider dependent<\/td><\/tr><tr><td>IMAP<\/td><td>143<\/td><td>Mail access<\/td><td>STARTTLS-capable<\/td><\/tr><tr><td>IMAP over TLS<\/td><td>993<\/td><td>Mail access<\/td><td>Implicit TLS<\/td><\/tr><tr><td>POP3<\/td><td>110<\/td><td>Mail access<\/td><td>STARTTLS-capable<\/td><\/tr><tr><td>POP3 over TLS<\/td><td>995<\/td><td>Mail access<\/td><td>Implicit TLS<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<figure class=\"wp-block-image\"><img decoding=\"async\" src=\"https:\/\/www.warmy.io\/blog\/wp-content\/uploads\/2026\/11\/smtp-vs-imap-pop3-sending-receiving.jpg\" alt=\"Comparison of SMTP ports 587 and 465 for sending email, IMAP ports 143 and 993, and POP3 ports 110 and 995 for receiving email.\" title=\"SMTP vs IMAP and POP3: Email Sending and Receiving Ports\"\/><\/figure>\n\n\n\n<p>Incoming mail can work perfectly while outgoing mail fails. In that situation, check the SMTP settings: the IMAP ports control mailbox access and have no role in the connection used to send.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Which Port Should You Actually Use?<\/h2>\n\n\n\n<p>A port number alone is not enough to configure submission. If the service expects STARTTLS but the application tries implicit TLS, the connection will fail even with the correct hostname.<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>Scenario<\/th><th>Port to use<\/th><th>Why<\/th><\/tr><\/thead><tbody><tr><td>Provider specifies STARTTLS submission<\/td><td>587<\/td><td>Registered Message Submission port<\/td><\/tr><tr><td>Provider specifies implicit TLS<\/td><td>465<\/td><td>RFC 8314 Message Submission over TLS<\/td><\/tr><tr><td>Gmail or Google Workspace client SMTP<\/td><td>587 or 465<\/td><td>Google documents 587 with TLS and 465 with SSL<\/td><\/tr><tr><td>Outlook.com<\/td><td>587<\/td><td>Microsoft specifies STARTTLS on 587<\/td><\/tr><tr><td>Microsoft 365 client SMTP submission<\/td><td>587 recommended<\/td><td>Microsoft&#8217;s documented client-submission configuration<\/td><\/tr><tr><td>Provider offers an alternate endpoint<\/td><td>2525<\/td><td>Provider-specific fallback<\/td><\/tr><tr><td>Mail-server-to-mail-server relay<\/td><td>25<\/td><td>Standard SMTP relay role<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<figure class=\"wp-block-image\"><img decoding=\"async\" src=\"https:\/\/www.warmy.io\/blog\/wp-content\/uploads\/2026\/11\/which-smtp-port-to-use-infographic.jpg\" alt=\"SMTP port selection infographic showing port 587 with STARTTLS, port 465 with implicit TLS, port 25 for server relay and port 2525 as a provider-supported fallback.\" title=\"Which SMTP Port Should You Use? 25, 465, 587 and 2525\"\/><\/figure>\n\n\n\n<p>For <code>smtp.gmail.com<\/code>, <a title=\"Google Gmail SMTP ports 465 and 587 configuration\" href=\"https:\/\/knowledge.workspace.google.com\/admin\/gmail\/send-email-from-a-printer-scanner-or-app?hl=en\" target=\"_blank\" rel=\"nofollow noopener noreferrer\">Google documents<\/a> port 465 for SSL and 587 for TLS. <a title=\"Gmail SMTP settings guide for ports 465 and 587\" href=\"https:\/\/www.warmy.io\/blog\/gmail-smtp-settings-guide-configuring-gmail-smtp\/\" target=\"_blank\" rel=\"noopener noreferrer\">Setting up Gmail SMTP specifically? See our step-by-step guide<\/a>.<\/p>\n\n\n\n<p>For Microsoft 365 client SMTP submission, <a title=\"Microsoft 365 SMTP port 587 client submission settings\" href=\"https:\/\/learn.microsoft.com\/en-us\/exchange\/mail-flow-best-practices\/how-to-set-up-a-multifunction-device-or-application-to-send-email-using-microsoft-365-or-office-365?WT.mc_id=AZ-MVP-5004810\" target=\"_blank\" rel=\"nofollow noopener noreferrer\">Microsoft lists<\/a> port 587 as recommended, with port 25 available for some configurations. <a title=\"Outlook SMTP settings guide for port 587 and STARTTLS\" href=\"https:\/\/www.warmy.io\/blog\/outlook-smtp-settings-guide-configuring-outlook-smtp\/\" target=\"_blank\" rel=\"noopener noreferrer\">Setting up Outlook SMTP specifically? See our step-by-step guide<\/a>.<\/p>\n\n\n\n<p>Check which service the account uses before matching SMTP IP and port settings. Take the hostname, authentication method, and documented mail port for SMTP submission from that provider&#8217;s guide. The TLS mode must match that endpoint too; settings from another provider can fail even when port numbers match.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">How a Wrong Port Choice Looks Like a Deliverability Problem<\/h2>\n\n\n\n<p>A wrong port can stop a message before it ever reaches the submission server. To the sender, it simply looks undelivered. There is no inbox-placement result to investigate yet because the application has not handed the message over.<\/p>\n\n\n\n<p>Start with the error reported by the application. A timeout or connection refusal calls for checking connectivity; a <a title=\"SMTP STARTTLS errors and TLS mismatch troubleshooting\" href=\"https:\/\/www.warmy.io\/blog\/smtp-starttls-errors-causes-fixes-how-to-ensure-secure-email-communication\/\" target=\"_blank\" rel=\"noopener noreferrer\">TLS error<\/a> calls for checking the encryption settings. In practice, <code>Connection timed out<\/code> or <code>Connection refused<\/code> usually means the port is blocked or wrong; <code>wrong version number<\/code> usually means the client tried implicit TLS on a port that expects STARTTLS; a session that hangs right after connecting on 465 often means the reverse; and <a title=\"SMTP error 530 5.7.0 STARTTLS command required troubleshooting\" href=\"https:\/\/www.warmy.io\/blog\/how-to-fix-smtp-email-error-530-solved\/\" target=\"_blank\" rel=\"noopener noreferrer\"><code>530 5.7.0 Must issue a STARTTLS command first<\/code><\/a> means the server wants encryption before anything else. Once connected, verify authentication and check the server&#8217;s response before investigating downstream delivery.<\/p>\n\n\n\n<figure class=\"wp-block-image\"><img decoding=\"async\" src=\"https:\/\/www.warmy.io\/blog\/wp-content\/uploads\/2026\/11\/smtp-port-error-vs-email-deliverability.jpg\" alt=\"Comparison of SMTP connection errors that prevent email submission and deliverability issues affecting inbox or spam placement after submission succeeds.\" title=\"SMTP Connection Errors vs Email Deliverability Problems\"\/><\/figure>\n\n\n\n<p>Changing <a title=\"SPF DKIM DMARC authentication errors and email deliverability setup\" href=\"https:\/\/www.warmy.io\/blog\/why-do-you-need-to-configure-spf-dkim-dmarc-and-how-to-set-them\/\" target=\"_blank\" rel=\"noopener noreferrer\">SPF, DKIM, DMARC<\/a>, or message content will not fix a failed connection or TLS handshake. A rejection needs a different investigation. Read the server&#8217;s explanation, which may point to authentication or a policy governing the message itself.<\/p>\n\n\n\n<p>Once submission succeeds, investigate downstream delivery and <a title=\"Free email deliverability test for inbox and spam placement\" href=\"https:\/\/www.warmy.io\/free-tools\/email-deliverability-test\/\" target=\"_blank\" rel=\"noopener noreferrer\">spam placement<\/a>. Switching between 465 and 587 will not improve sender reputation; the correct mail port for SMTP only satisfies a connection requirement.<\/p>\n\n\n\n<p>You can also <a title=\"Warmy Deliverability Insights for SMTP authentication and domain setup\" href=\"https:\/\/www.warmy.io\/product\/deliverability\/\" target=\"_blank\" rel=\"noopener noreferrer\">check your domain&#8217;s overall SMTP and authentication setup<\/a> with Warmy&#8217;s Deliverability Insights.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Common SMTP Port Mistakes<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Using port 25 as the default for a client or application without checking the provider&#8217;s submission settings.<\/li>\n\n\n\n<li>Calling port 465 deprecated because an older guide still says so.<\/li>\n\n\n\n<li>Configuring STARTTLS where the provider expects implicit TLS, or the reverse.<\/li>\n\n\n\n<li>Treating port 2525 as a universal fallback.<\/li>\n\n\n\n<li>Confusing SMTP sending settings with IMAP or POP3 receiving settings.<\/li>\n\n\n\n<li>Changing an SMTP mail port to troubleshoot spam placement after submission already succeeds.<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">FAQ<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">What SMTP port should I use for sending email?<\/h3>\n\n\n\n<p>Follow your provider&#8217;s documented port and encryption settings. For authenticated submission, the usual choices are 587 with STARTTLS or 465 with implicit TLS.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Is SMTP port 465 deprecated?<\/h3>\n\n\n\n<p>No. RFC 8314 specifies TCP 465 for Message Submission over TLS, and IANA registers it as <code>submissions<\/code>.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Why is SMTP port 25 blocked by most providers?<\/h3>\n\n\n\n<p>Restricting port 25 helps reduce spam sent directly to recipient mail servers. Authorized servers can still use it for relay.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">What&#8217;s the difference between port 587 and port 465?<\/h3>\n\n\n\n<p>Port 587 commonly uses STARTTLS to upgrade an existing SMTP session. On 465, TLS negotiation begins immediately, before any SMTP data is exchanged.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">What is port 2525, and when should I use it?<\/h3>\n\n\n\n<p>An unofficial SMTP alternative, 2525 is useful when the usual port is unavailable, provided your email service supports it.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Do SMTP ports affect email deliverability?<\/h3>\n\n\n\n<p>Only indirectly. A wrong port stops the message before your provider accepts it, which can look like a deliverability problem. Once the message is accepted, the port number has no effect on inbox or spam placement.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">What port does Gmail use for SMTP?<\/h3>\n\n\n\n<p>Google documents port 587 with TLS and port 465 with SSL for <code>smtp.gmail.com<\/code>.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Is SMTP port the same for sending and receiving email?<\/h3>\n\n\n\n<p>No. SMTP sends or relays mail. IMAP and POP3 are used to access received mail.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">What happens if I use the wrong SMTP port?<\/h3>\n\n\n\n<p>The message never leaves your app. Depending on the mismatch, you&#8217;ll see a timeout, a refused connection, a TLS error, or an authentication failure &#8211; not a spam-folder placement.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Does changing my SMTP port fix emails going to spam?<\/h3>\n\n\n\n<p>No. If submission already works, investigate spam placement rather than changing the port.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Wrapping Up<\/h2>\n\n\n\n<p>For an email client or app, follow the provider&#8217;s documented SMTP port and TLS settings. If the normal submission connection is unavailable, check whether the provider offers 2525 as an alternative.<\/p>\n\n\n\n<p>After the provider accepts a message, inbox placement depends on factors such as email authentication and sender reputation. For a closer look at delivery beyond the submission connection, explore <a title=\"Warmy Deliverability Insights for SMTP setup and email inbox placement\" href=\"https:\/\/www.warmy.io\/product\/deliverability\/\" target=\"_blank\" rel=\"noopener noreferrer\">Warmy&#8217;s Deliverability Insights<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Short answer: to send from an app, CRM, or email client, use SMTP port 587 with STARTTLS, or 465 with implicit TLS if your provider asks for it. Port 25 is for server-to-server relay, and 2525 is a fallback when a network blocks the others. An email client hands outgoing mail to a provider for [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":9163,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[104],"tags":[],"class_list":["post-9168","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-email-deliverability"],"acf":[],"lang":"en","translations":{"en":9168},"pll_sync_post":[],"_links":{"self":[{"href":"https:\/\/www.warmy.io\/blog\/wp-json\/wp\/v2\/posts\/9168","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.warmy.io\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.warmy.io\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.warmy.io\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.warmy.io\/blog\/wp-json\/wp\/v2\/comments?post=9168"}],"version-history":[{"count":1,"href":"https:\/\/www.warmy.io\/blog\/wp-json\/wp\/v2\/posts\/9168\/revisions"}],"predecessor-version":[{"id":9169,"href":"https:\/\/www.warmy.io\/blog\/wp-json\/wp\/v2\/posts\/9168\/revisions\/9169"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.warmy.io\/blog\/wp-json\/wp\/v2\/media\/9163"}],"wp:attachment":[{"href":"https:\/\/www.warmy.io\/blog\/wp-json\/wp\/v2\/media?parent=9168"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.warmy.io\/blog\/wp-json\/wp\/v2\/categories?post=9168"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.warmy.io\/blog\/wp-json\/wp\/v2\/tags?post=9168"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}