{"id":95,"date":"2026-11-09T05:31:08","date_gmt":"2026-11-09T05:31:08","guid":{"rendered":"https:\/\/digitalbondgroup.com.au\/?p=95"},"modified":"2026-11-09T05:32:42","modified_gmt":"2026-11-09T05:32:42","slug":"microsoft-365-email-delivery-failure-spf-error-550-5-7-23","status":"publish","type":"post","link":"https:\/\/digitalbondgroup.com.au\/?p=95","title":{"rendered":"Microsoft 365 Email Delivery Failure \u2013 SPF Error 550 5.7.23"},"content":{"rendered":"\n<h2 class=\"wp-block-heading\">Problem Description<\/h2>\n\n\n\n<p>A Microsoft 365 mailbox hosted through GoDaddy had been working normally for several years. However, starting in early November 2026, outgoing emails to Outlook.com \/ Hotmail recipients began generating delivery failure notifications.<\/p>\n\n\n\n<p>The error reported was:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>550 5.7.23 The message was rejected because of\nSender Policy Framework violation\n\n550 5.7.1 Message rejected:\nMessage lacks SPF\/DKIM\/DMARC Auth Records (AS9031519)<\/code><\/pre>\n\n\n\n<p>Interestingly, the issue appeared to affect Outlook.com \/ Hotmail recipients, while there was no indication of a general outbound email service failure.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Investigation<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">1. Checked the existing SPF record<\/h3>\n\n\n\n<p>The domain&#8217;s DNS TXT records were checked using:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>nslookup -type=TXT yourdomain.com<\/code><\/pre>\n\n\n\n<p>The existing SPF record was:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>v=spf1 include:secureserver.net -all<\/code><\/pre>\n\n\n\n<p>This is the standard SPF configuration recommended for Microsoft 365 services hosted through GoDaddy.<\/p>\n\n\n\n<p>There were no duplicate SPF records, and no other email servers were being used to send emails on behalf of the domain.<\/p>\n\n\n\n<p>Therefore, the existing SPF record was left unchanged.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">2. Checked the DMARC record<\/h3>\n\n\n\n<p>The following command was used:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>nslookup -type=TXT _dmarc.yourdomain.com<\/code><\/pre>\n\n\n\n<p>The result indicated that no DMARC record existed:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>Non-existent domain<\/code><\/pre>\n\n\n\n<p>This revealed a missing email authentication configuration.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Solution<\/h2>\n\n\n\n<p>A DMARC TXT record was added through the GoDaddy DNS management interface.<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><tbody><tr><th>Field<\/th><th>Value<\/th><\/tr><tr><td>Type<\/td><td>TXT<\/td><\/tr><tr><td>Host \/ Name<\/td><td><code>_dmarc<\/code><\/td><\/tr><tr><td>Value<\/td><td><code>v=DMARC1; p=none<\/code><\/td><\/tr><tr><td>TTL<\/td><td>Default<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>The <code>p=none<\/code> policy enables DMARC authentication and monitoring without instructing receiving mail servers to quarantine or reject messages that fail DMARC validation.<\/p>\n\n\n\n<p>After adding the record, DNS propagation was verified using:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>nslookup -type=TXT _dmarc.yourdomain.com<\/code><\/pre>\n\n\n\n<p>The expected result was returned:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>v=DMARC1; p=none<\/code><\/pre>\n\n\n\n<h2 class=\"wp-block-heading\">Verification<\/h2>\n\n\n\n<p>After the DMARC record was published, two emails that had previously failed delivery were sent again to the affected recipients.<\/p>\n\n\n\n<p>Both emails were sent successfully, with no further delivery failure notifications received at the time of testing.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Conclusion<\/h2>\n\n\n\n<p>The issue appears to have been resolved by adding a DMARC DNS record.<\/p>\n\n\n\n<p>The existing SPF configuration was already correct for GoDaddy-hosted Microsoft 365 and did not need modification.<\/p>\n\n\n\n<p><strong>Key takeaway:<\/strong> If Microsoft 365 emails suddenly start failing delivery to Outlook.com \/ Hotmail with error <code>550 5.7.23<\/code>, check all three email authentication mechanisms:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>SPF \u2013 Ensure the sending service is authorised.<\/li>\n\n\n\n<li>DKIM \u2013 Ensure outgoing messages are digitally signed.<\/li>\n\n\n\n<li>DMARC \u2013 Ensure a valid DMARC policy is published in DNS.<\/li>\n<\/ul>\n\n\n\n<p>Even when SPF is correctly configured, the absence of a DMARC record may contribute to email authentication and delivery problems.<\/p>\n\n\n\n<p><strong>Note:<\/strong> The successful tests suggest that adding DMARC resolved this particular issue, but they do not conclusively establish the underlying cause of Microsoft&#8217;s rejection. DKIM status was not independently verified during this troubleshooting process, and further monitoring is recommended.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Problem Description A Microsoft 365 mailbox hosted through GoDaddy had been working normally for several years. However, starting in early November 2026, outgoing emails to &hellip; <span class=\"more-button\"><a href=\"https:\/\/digitalbondgroup.com.au\/?p=95\" class=\"more-link\">Continue Reading<span class=\"screen-reader-text\">Microsoft 365 Email Delivery Failure \u2013 SPF Error 550 5.7.23<\/span><\/a><\/span><\/p>\n","protected":false},"author":1,"featured_media":86,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[11,10],"tags":[],"class_list":["post-95","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-email-issues","category-office-it-support"],"jetpack_featured_media_url":"https:\/\/i0.wp.com\/digitalbondgroup.com.au\/wp-content\/uploads\/2023\/10\/brett-jordan-LPZy4da9aRo-unsplash.jpg?fit=1920%2C1440&ssl=1","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/digitalbondgroup.com.au\/index.php?rest_route=\/wp\/v2\/posts\/95"}],"collection":[{"href":"https:\/\/digitalbondgroup.com.au\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/digitalbondgroup.com.au\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/digitalbondgroup.com.au\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/digitalbondgroup.com.au\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=95"}],"version-history":[{"count":1,"href":"https:\/\/digitalbondgroup.com.au\/index.php?rest_route=\/wp\/v2\/posts\/95\/revisions"}],"predecessor-version":[{"id":96,"href":"https:\/\/digitalbondgroup.com.au\/index.php?rest_route=\/wp\/v2\/posts\/95\/revisions\/96"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/digitalbondgroup.com.au\/index.php?rest_route=\/wp\/v2\/media\/86"}],"wp:attachment":[{"href":"https:\/\/digitalbondgroup.com.au\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=95"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/digitalbondgroup.com.au\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=95"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/digitalbondgroup.com.au\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=95"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}