{"id":3881,"date":"2024-05-06T13:32:57","date_gmt":"2024-05-06T13:32:57","guid":{"rendered":"https:\/\/www.warmy.io\/blog\/how-to-fix-smtp-email-error-422-solved\/"},"modified":"2026-04-05T11:26:37","modified_gmt":"2026-04-05T11:26:37","slug":"how-to-fix-smtp-email-error-422-solved","status":"publish","type":"post","link":"https:\/\/www.warmy.io\/blog\/how-to-fix-smtp-email-error-422-solved\/","title":{"rendered":"SMTP Error 422: Recipient Mailbox Storage Limit Exceeded \u2014 Causes and Fixes"},"content":{"rendered":"<p><span>Most SMTP errors are head scratchers. But one that arguably takes the bag is <strong>SMTP Error <\/strong><\/span><strong>422: Unprocessable Entity.\u201d<\/strong><\/p>\n<p><span>This error pertains to the contents of the email which can be subjective especially with varying email servers and providers in the digital landscape.\u00a0<\/span><\/p>\n<p><span>For this blog post, we will discuss what SMTP Error 422 is and the possible solutions to resolve and avoid it.<\/span><\/p>\n<h2>SMTP Error 422: The unprocessable entity<\/h2>\n<p><span>SMTP Error 422 usually comes with the error message \u201c<strong>422 Unprocessable Entity.<\/strong>\u201d <\/span><\/p>\n<p><span>This error pertains to issues within the email content, which can <\/span><span>be found in the email body, headers, or attachments.\u00a0<\/span><\/p>\n<p><span>In some cases, this error can also signify that there is an error in the email setting configuration or the email compatibility that disrupts SMTP functions.<\/span><\/p>\n<h2>What causes SMTP Error 422?<\/h2>\n<p>Here are the usual reasons why this error occurs.<\/p>\n<h3>Message formatting issues<\/h3>\n<ul>\n<li><strong>Encoding problems.<\/strong> <span>\u00a0If the email is encoded in a format that the server cannot interpret, the server might reject the message.<\/span><\/li>\n<li><strong>HTML\/CSS issues.<\/strong> Emails that use complex HTML or CSS may be problematic for servers that are configured to handle only plain text or simple HTML. In some cases, the SMTP Error 422 will not occur, but these emails may be sent to the <a href=\"https:\/\/www.warmy.io\/blog\/from-spam-folder-to-inbox-mastering-email-deliverability-basics\/\" target=\"_blank\" rel=\"noopener noreferrer\">spam folder<\/a> instead.<\/li>\n<\/ul>\n<h3>Email header errors<\/h3>\n<ul>\n<li><strong>Incorrect headers.<\/strong>\u00a0Headers that are malformed or contain erroneous information can lead to rejections by the email server.<\/li>\n<li><strong>Incomplete headers.<\/strong> Missing critical header information can prevent the server from processing the email correctly.<\/li>\n<\/ul>\n<p>Interested in details? Check out our article on <a href=\"https:\/\/www.warmy.io\/blog\/how-to-use-an-email-header-analyzer-for-better-email-security\/\" target=\"_blank\" rel=\"noopener noreferrer\">How to Use an Email Header Analyzer for Better Email Security<\/a>.<\/p>\n<h3>Content that the server fails to process<\/h3>\n<ul>\n<li><strong>Unsupported media types.<\/strong> Some attachments or embedded media aren\u2019t supported by specific server.<\/li>\n<li><strong>Security policies.<\/strong> Many servers have strict security policies regarding the types of content they will accept. For example, executable files or links to suspicious sources may be automatically rejected.<\/li>\n<\/ul>\n<h3>Configuration and policy restrictions<\/h3>\n<ul>\n<li><strong>Anti-spam filters.<\/strong>\u00a0Servers often use sophisticated algorithms to filter out spam. Emails that accidentally trigger these filters due to certain keywords or patterns might be stopped.<\/li>\n<li><strong>Size limits.<\/strong>\u00a0Emails that exceed the maximum allowed size can also result in a 422 error if the server decides it cannot process such large messages.<\/li>\n<\/ul>\n<h2>How to fix SMTP Email Error 422: A step-by-step guide<\/h2>\n<h3>For Gmail<\/h3>\n<ol>\n<li>\n<p><strong>Verify and Adjust SMTP Settings<\/strong>:<\/p>\n<ul>\n<li>Go to the Gmail settings page and select \u2018See all settings\u2019.<\/li>\n<li>Click on the \u2018Accounts and Import\u2019 tab and find the \u2018Send mail as\u2019 section.<\/li>\n<li>Click on \u2018Edit info\u2019 and then \u2018Next Step\u2019 to view SMTP settings.<\/li>\n<li>Ensure that the SMTP server is set to \u2018smtp.gmail.com\u2019, the port is either 587 (with TLS) or 465 (with SSL), and the correct username and password are entered.<\/li>\n<\/ul>\n<\/li>\n<li>\n<p><strong>Check the format of outgoing emails<\/strong>:<\/p>\n<ul>\n<li>When composing an email, avoid using overly complex HTML or unusual characters that might not be supported.<\/li>\n<li>Test sending plain text emails to see if the error persists, which can help isolate the issue to content formatting.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n<h3>For Outlook<\/h3>\n<ol>\n<li>\n<p><strong>Correct header information and ensure configurations are up-to-date<\/strong>:<\/p>\n<ul>\n<li>Open Outlook and go to \u2018File\u2019 &gt; \u2018Info\u2019 &gt; \u2018Account Settings\u2019 &gt; \u2018Server Settings\u2019.<\/li>\n<li>Check the \u2018Outgoing mail\u2019 settings to ensure the SMTP settings are correct: typically, <code>smtp-mail.outlook.com<\/code> with port 587.<\/li>\n<li>Ensure that \u2018My outgoing (SMTP) server requires authentication\u2019 is checked.<\/li>\n<\/ul>\n<\/li>\n<li>\n<p><strong>Troubleshoot and use diagnostic tools<\/strong>:<\/p>\n<ul>\n<li>Use the Microsoft Support and Recovery Assistant tool to automatically diagnose and fix issues with your Outlook profile and SMTP settings.<\/li>\n<li>If manual configuration is needed, carefully review and adjust the headers by editing the account settings and ensuring all entries are correctly formatted.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n<h3>For Yahoo<\/h3>\n<ol>\n<li>\n<p><strong>Reviewing and Modifying SMTP Configurations<\/strong>:<\/p>\n<ul>\n<li>Access the \u2018Account Info\u2019 page in your Yahoo account.<\/li>\n<li>Navigate to \u2018Account Security\u2019 and scroll down to \u2018Manage app passwords\u2019.<\/li>\n<li>Use this feature to generate a unique password if you\u2019re using third-party email clients and ensure SMTP settings are aligned with Yahoo\u2019s requirements: <code>smtp.mail.yahoo.com<\/code>, port 465 or 587.<\/li>\n<\/ul>\n<\/li>\n<li>\n<p><strong>Sending Test Emails<\/strong>:<\/p>\n<ul>\n<li>Send a few simple test emails to different addresses to see if the issue resolves.<\/li>\n<li>If errors persist, reduce the complexity of the email content and try sending again.<\/li>\n<li>Document what changes were made when the email was successful to identify what triggered the error.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n<h2><a href=\"https:\/\/www.warmy.io\/\" target=\"_blank\" rel=\"noopener noreferrer\">How to combat SMTP Error 422 with Warmy.io<\/a><\/h2>\n<p><img loading=\"lazy\" decoding=\"async\" alt=\"Screenshot of Warmy\u2019s homepage showing a banner that reads: \u201cAuto All-In-One Tool For Email Deliverability To Make Your Email Channel Reliable,\u201d with buttons for booking a demo and exploring a 7-day trial\u2014perfect for those who want to maximize COB meaning in email.\" height=\"600\" src=\"https:\/\/warmy-blog-wordpress-bucket.s3.amazonaws.com\/wp-content\/uploads\/2025\/09\/22061920\/Warmy-Homepage-1024x768.webp\" width=\"800\" title=\"\"><\/p>\n<p><a href=\"https:\/\/www.warmy.io\/\" target=\"_blank\" rel=\"noopener noreferrer\"><span>Warmy.io<\/span><\/a><span> provides a suite of tools and services designed to enhance email deliverability and prevent issues like SMTP Error 422 from arising. <\/span><span>Here\u2019s how you can utilize Warmy.io to improve your email system\u2019s reliability and effectiveness:<\/span><\/p>\n<h3>Template Checker<\/h3>\n<p><img loading=\"lazy\" decoding=\"async\" alt=\"A user interface displays an email template focused on improving deliverability, with subject and message fields on the left and template analysis on the right, showing stats like subject length, word count, and personalization score.\" height=\"600\" src=\"https:\/\/warmy-blog-wordpress-bucket.s3.amazonaws.com\/wp-content\/uploads\/2025\/05\/15090244\/template-checker-1.webp\" width=\"800\" title=\"\"><\/p>\n<p><span>Warmy provides guidance on how to craft content that avoids common spam filters. The<\/span><a href=\"https:\/\/www.warmy.io\/free-tools\/template-checker\" target=\"_blank\" rel=\"noopener noreferrer\"><span> template checker<\/span><\/a><span> analyzes your email to ensure that it complies with best practices for avoiding the spam folder, thus reducing the likelihood of getting the SMTP Errpr 422.<\/span><\/p>\n<p><span>Additionally, Warmy offers a<\/span><a href=\"https:\/\/chromewebstore.google.com\/detail\/email-template-checker-wa\/oelldnebggajjfacfajacfbkeekeakip\" rel=\"noopener\" target=\"_blank\" rel=\"noopener noreferrer\"><span> Chrome Extension version of the template checker<\/span><\/a><span>. This extension helps you assess whether your email is likely to be flagged by spam filters, enabling you to make necessary adjustments before sending. With this extension, you will be able to better determine whether your email will be recognized as spam and make tweaks before sending it.<\/span><\/p>\n<h3>AI-powered email warmup<\/h3>\n<p><img loading=\"lazy\" decoding=\"async\" alt=\"Graph showing email warmup performance with a line chart which helps with email sender reputation score. The x-axis represents dates from June 1 to June 9, and the y-axis represents email volume. Two lines indicate sent (1,200) and received (1,100) emails. Background is a soft gradient.\" height=\"600\" src=\"https:\/\/warmy-blog-wordpress-bucket.s3.amazonaws.com\/wp-content\/uploads\/2025\/03\/11092911\/8shots_so-1.webp\" width=\"800\" title=\"\"><\/p>\n<p><span>Warmy.io\u2019s automated email warmup services are crucial for anyone starting with a new email account or domain. <\/span><\/p>\n<p><span>By gradually increasing the sending volume and ensuring they engage positively with recipients, the warmup process helps build a positive sender reputation which reduces the likelihood of SMTP errors.<\/span><\/p>\n<p><span>These services include automated interactions with emails to mimic genuine engagement, which is vital for maintaining good standing with email service providers and avoiding automatic filtering or temporary blocks.<\/span><\/p>\n<h3>Free email deliverability test and record generators<br \/>\n<\/h3>\n<p><img loading=\"lazy\" decoding=\"async\" alt=\"A digital dashboard titled Email Deliverability Test shows a summary of results. A circular graph indicates 9 hours to completion. Charts below display placement percentages across platforms like Gmail, Outlook, and Yahoo.\" height=\"600\" src=\"https:\/\/warmy-blog-wordpress-bucket.s3.amazonaws.com\/wp-content\/uploads\/2025\/03\/11093353\/562shots_so-1.webp\" width=\"800\" title=\"\"><\/p>\n<p>Warmy.io offers <a href=\"https:\/\/www.warmy.io\/free-tools\/email-deliverability-test\" target=\"_blank\" rel=\"noopener noreferrer\">email deliverability tests<\/a> that analyze your email setup to identify potential deliverability issues. These tests can check for common pitfalls that might lead to SMTP errors, such as incorrect configuration settings or problematic content.<\/p>\n<p><a href=\"https:\/\/www.warmy.io\/free-tools\/spf-generator\" target=\"_blank\" rel=\"noopener noreferrer\">SPF<\/a> and <a href=\"https:\/\/www.warmy.io\/free-tools\/dmarc-generator\" target=\"_blank\" rel=\"noopener noreferrer\">DMARC<\/a> Record Generators.\u00a0Proper setup of SPF (Sender Policy Framework) and DMARC (Domain-based Message Authentication, Reporting &amp; Conformance) records is crucial for authenticating your email and ensuring it is trusted by receiving servers. Warmy.io provides free tools to generate these records accurately, further bolstering your defense against SMTP errors.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" alt=\"A website interface titled Free DMARC Record Generator with a form to enter a domain for generating a DMARC record. Below the title are navigation buttons for Domain, ESP, Email, and DMARC value. A Next button is at the bottom.\" height=\"600\" src=\"https:\/\/warmy-blog-wordpress-bucket.s3.amazonaws.com\/wp-content\/uploads\/2025\/03\/11093355\/848shots_so.webp\" width=\"800\" title=\"\"><\/p>\n<h2>Make sure your message gets through<\/h2>\n<p><span>Ensuring proper email formats, identifying correct headers, and guaranteeing that your attachments are compatible with the email you are sending are some of the best solutions to avoid getting errors such as the SMTP 422.\u00a0<\/span><\/p>\n<p><span>Simple errors like these have significant weight that may disrupt your overall deliverability and business bottom line.<\/span><\/p>\n<p><span>Taking advantage of tools such as <\/span><a href=\"https:\/\/www.warmy.io\/\" target=\"_blank\" rel=\"noopener noreferrer\"><span>Warmy.io<\/span><\/a><span> ensures that you deliver the perfect email content, and review your SMTP settings. <a href=\"https:\/\/www.warmy.io\/signup\" target=\"_blank\" rel=\"noopener noreferrer\">Sign up for your free trial today.<\/a><\/span><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Most SMTP errors are head scratchers. But one that arguably takes the bag is SMTP Error 422: Unprocessable Entity.\u201d This error pertains to the contents of the email which can be subjective especially with varying email servers and providers in the digital landscape.\u00a0 For this blog post, we will discuss what SMTP Error 422 is [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[104],"tags":[],"class_list":["post-3881","post","type-post","status-publish","format-standard","hentry","category-email-deliverability"],"acf":[],"lang":"en","translations":{"en":3881},"pll_sync_post":[],"_links":{"self":[{"href":"https:\/\/www.warmy.io\/blog\/wp-json\/wp\/v2\/posts\/3881","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=3881"}],"version-history":[{"count":1,"href":"https:\/\/www.warmy.io\/blog\/wp-json\/wp\/v2\/posts\/3881\/revisions"}],"predecessor-version":[{"id":5731,"href":"https:\/\/www.warmy.io\/blog\/wp-json\/wp\/v2\/posts\/3881\/revisions\/5731"}],"wp:attachment":[{"href":"https:\/\/www.warmy.io\/blog\/wp-json\/wp\/v2\/media?parent=3881"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.warmy.io\/blog\/wp-json\/wp\/v2\/categories?post=3881"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.warmy.io\/blog\/wp-json\/wp\/v2\/tags?post=3881"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}