Error code 550 5.7.x in Microsoft Exchange

<h2 id="h_01HB6CD3MHPJ4MAP723BXKQ9CB">Issue symptoms</h2><ul>
<li data-list-item-id="e8ba135cb44c2496be3d1fd67af638d77">End users receive a bounce-back notification from Microsoft after they send an email to a support address</li>
<li data-list-item-id="ee8319ba22e4d69b73d5c4f563d8ff930">The notification starts with: Your message could not be delivered</li>
<li data-list-item-id="e656b0add430efa4aa1bd4d4ac92382b2">The message includes an error or status code with <code>550 5.7.x</code>
</li>
<li data-list-item-id="e3010237a688041edb15509f77dc97d48">Another message might look like: <strong>550 5.7.520 Access denied, Your organization does not allow external forwarding. Please contact your administrator for further assistance. AS(7555).</strong>
</li>
<li data-list-item-id="e2291f416d26cd8577b9b4875735488ff">The emails don't reach Zendesk</li>
</ul><p>The text of the message will be different for each underlying issue. However, the main problem remains the same: the user's email was rejected before it could reach Zendesk.</p><h2 id="h_01M1C45JBTXJKKVVQME7XBGE2B">Root cause</h2><p>Typically, these errors are linked to the fact that:</p><ul>
<li data-list-item-id="e0f0d0eda7227670661ba1d9dcab7fe95">Your organization may not allow external forwarding in Microsoft</li>
<li data-list-item-id="e4035a1de2f311c4bf3f51c2a54367f3c">Additional settings in Microsoft Exchange prevent you from automatically forwarding emails</li>
<li data-list-item-id="e510c233a2f60a70fe7832caf0de3f0af">Microsoft may have updated its policies around <a href="https://learn.microsoft.com/en-us/microsoft-365/security/office-365-security/outbound-spam-policies-external-email-forwarding?view=o365-worldwide" target="_blank" rel="noopener noreferrer">automatic email forwarding</a>, and it may affect support addresses that synced in the past. This type of error can occur on a support address that previously worked. That typically means something has changed. For example, if Microsoft implements a new policy for email forwarding, previous addresses may not meet the new requirements without an update. For more information, see <a href="https://support.zendesk.com/hc/en-us/articles/4408886828698-Forwarding-incoming-email-from-your-existing-email-address-to-Zendesk-Support" target="_blank" rel="noopener noreferrer">Forwarding incoming email from your existing email address to Zendesk Support</a>.</li>
</ul><div class="p">
<div class="note">
<span class="notetitle">Disclaimer:</span> These errors are generated by Microsoft, not Zendesk. Zendesk cannot assist in resolving these errors. Rules or spam policies of Microsoft 365 may affect external forwarding. If the resolution steps don't seem to apply to you, or if the issue continues after you change your outbound spam protection settings, contact <a href="https://support.microsoft.com/en-us/topic/contact-microsoft-office-support-fd6bb40e-75b7-6f43-d6f9-c13d10850e77" target="_blank" rel="noopener noreferrer">Microsoft Support</a> for help.</div>
<h2 id="h_01HB6CD3MH8QTRMB54A5R6THQ6">Resolution steps</h2>
<ol>
<li data-list-item-id="edbeb1298f88b330f9b32f0cfbd669033">If your users suddenly report bounce-back notifications and error messages, contact the <a href="https://support.microsoft.com/en-us/office/how-do-i-find-my-microsoft-365-admin" target="_blank" rel="noopener noreferrer">Microsoft administrator</a> in your company</li>
<li data-list-item-id="ea8dacdfbe6fb7d2e40ec6a8768351c88">Your administrator needs to review the error message and correct your email configuration accordingly outside of Zendesk with the guidance below</li>
<li data-list-item-id="ee16e59423e323c3e99937c1ec11f3aa5">Ask your administrator to verify your <a href="https://learn.microsoft.com/en-us/microsoft-365/security/office-365-security/outbound-spam-policies-external-email-forwarding" target="_blank" rel="noopener noreferrer">outbound spam filter policy</a> &gt; Set your <strong>Automatic forwarding</strong> to <strong>On</strong>, instead of <strong>Automatic - System-controlled</strong>
</li>
<li data-list-item-id="eaefb79d14cd89dd8f8a2579797235832">Configure your <a href="https://learn.microsoft.com/en-us/exchange/mail-flow-best-practices/remote-domains/manage-remote-domains" target="_blank" rel="noopener noreferrer">remote domain settings</a> to allow automatic email forwarding to some or all external domains. Don't disable auto-forwarding on your default remote domain, as when users try to auto-forward an email to another domain, they can change their settings or create the inbox rule, but their messages will not be transmitted.</li>
<li data-list-item-id="e37bc8051da8a6960741ef6288181cc9c">Ensure your administrator didn't set up any <a href="https://learn.microsoft.com/en-us/exchange/security-and-compliance/mail-flow-rules/manage-mail-flow-rules" target="_blank" rel="noopener noreferrer">conditions and actions</a> in Exchange mail flow rules, also known as transport rules, to detect and block automatically forwarded messages to external recipients</li>
<li data-list-item-id="eae7b5054def51b4bfb192680dd986afc">When your administrator corrects the settings in Microsoft Exchange, ask your Zendesk admin to access <strong>Zendesk</strong> &gt; <strong>Admin Center</strong> &gt; <strong>Channels</strong> &gt; <strong>Voice and email</strong> &gt; <strong>Email</strong> &gt; Manage support addresses &gt; Click the options menu icon next to your Microsoft email address, select <strong>Verify forwarding</strong> &gt; Ensure that no error appears</li>
<li data-list-item-id="e492a892087db6ed8940a1c0032b875c7">Alternatively, connect your non-Zendesk email servers, based on Microsoft Exchange, to your Zendesk account with the latest Microsoft Exchange connector</li>
</ol>
<h2 id="h_01M1P2RZGGHD75P30SM29T66NK">Error code 550 5.7.68: Reject Direct Send not allowed</h2>
<p>If the delivery failure includes <code>550 5.7.68 TenantInboundAttribution;</code> <strong>Direct Send</strong> not allowed for this organization from unauthorized sources, <strong>Reject Direct Send</strong> is enabled in Microsoft Exchange. This setting prevents Zendesk from sending messages because Zendesk is not recognized as an authorized sender for your email domain.</p>
<p>Ask your email administrator to verify the configuration of your external support address and allow Zendesk to send email on behalf of your domain.</p>
<p>If the issue continues, consider one of the following options:</p>
<ul>
<li data-list-item-id="e068d653a45d7a695fca3be8272796c2f">Connect your Exchange server using the Exchange Connector. This allows you to keep Reject Direct Send enabled while your Exchange server sends Zendesk notifications.</li>
<li data-list-item-id="eecb3f1d370e6aeba5d9293f18746764f">Create a Microsoft Exchange transport rule to block, redirect, or quarantine unwanted email while exempting Zendesk messages. Zendesk emails can be identified by the <code>X-Mailer: Zendesk Mailer</code> header.</li>
</ul>
<p>Contact Microsoft for help configuring Exchange policies or transport rules. Zendesk Support cannot provide guidance on the specific Exchange configuration required.</p>
<p>For more information, see:</p>
<ul>
<li data-list-item-id="e1e63407308e344199a3fc249cadec702"><a href="https://docs.microsoft.com/en-us/microsoft-365/security/office-365-security/external-email-forwarding?view=o365-worldwide" target="_blank" rel="noopener noreferrer">Control automatic external email forwarding in Microsoft 365</a></li>
<li data-list-item-id="e63606e323cc77b6531710449bbc81697">
<p><a href="https://support.zendesk.com/hc/en-us/articles/8994395472922-Connecting-your-Microsoft-Exchange-account-to-Zendesk" target="_blank" rel="noopener noreferrer">Connecting your Microsoft Exchange account to Zendesk</a></p>
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<h2 id="h_01M1C60X6EP4TH9KAEMSY0JYRJ">
Why do emails to my support address bounce back with
"550 5.7.x"? Why am I getting "550 5.7.520 Access denied,
Your organization does not allow external forwarding"?
Why do end user emails fail to reach Zendesk from Microsoft?
</h2>
<p>
This error occurs when Microsoft blocks external email
forwarding before messages reach Zendesk. Your organization
might restrict external forwarding in Microsoft Exchange,
or Microsoft policy changes affect your email forwarding
setup. Microsoft generates these delivery errors, not
Zendesk.
</p>
<h2 id="h_01M1C60X6ETJBEBMQP1H4P5XT8">
How do I fix Microsoft email bounce-back errors when
forwarding to Zendesk? How do I resolve "Your message
could not be delivered" for my support address? How do
I enable external email forwarding in Microsoft Exchange
for Zendesk?
</h2>
<p>
To resolve email forwarding errors from Microsoft Exchange
to Zendesk, update your email settings outside of Zendesk
and verify forwarding:
</p>
<ol>
<li>
Ask your Microsoft administrator to review your outbound
spam filter policy and set <strong>Automatic forwarding</strong>
to <strong>On</strong> instead of
<strong>Automatic - System-controlled</strong>.
</li>
<li>
Configure your remote domain settings in Microsoft
Exchange to allow automatic email forwarding to external
domains.
</li>
<li>
Ensure your Microsoft administrator did not set up
Exchange mail flow rules to detect and block automatically
forwarded messages.
</li>
<li>
Go to <strong>Zendesk</strong> &gt;
<strong>Admin Center</strong> &gt; <strong>Channels</strong>
&gt; <strong>Voice and email</strong> &gt;
<strong>Email</strong>.
</li>
<li>
Under Manage support addresses, click the options
menu icon next to your Microsoft email address and
select <strong>Verify forwarding</strong>.
</li>
<li>
Alternatively, connect your Microsoft Exchange server
to your Zendesk account using the Microsoft Exchange
connector.
</li>
</ol>
</details>
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</li>
</ul>
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