If you have setup a forwarding rule in Outlook 365/Office 365, to forward all emails to GMAIL or to another external email account, and the delivery fails with error "Remote Server returned '550 5.7.520 Access denied, Your organization does not allow external forwarding", continue reading below to resolve the problem.
Some months ago I enabled automatic forwarding in Outlook 365, to forward all my Office 365 emails to Gmail, and the forwarding rule worked fine a few months now. But today, the forwarding rule stopped working without an obvious reasons with error:
"Delivery has failed to these recipients or groups: firstname.lastname@example.org Your message wasn't delivered because the recipient's email provider rejected it. Diagnostic information for administrators: Generating server: SN6PR0102MB3373.prod.exchangelabs.com @xxx.com Remote Server returned '550 5.7.520 Access denied, Your organization does not allow external forwarding. Please contact your administrator for further assistance. AS(7555)'"
How to FIX: Office 365 Forwarding Not Working. Delivery has failed. Your organization does not allow external forwarding. 550 5.7.520 Access Denied.
Outlook 365 forwarding error "Delivery failed, your organization does not allow external forwarding – Remote Server returned.'550 5.7.520 Access denied", may occur for the following reasons:
- Reason 1. When you enabled email forwarding for more than ten (10) recipients. At this case, proceed and create a distribution group with these recipients, and forward to this distribution list instead, because Office 365 doesn't allow to auto-forward emails to more than 10 email addresses.
- Reason 2. When email forwarding is disabled in Office 365 Outbound Spam filter policies. At this case, to fix the forwarding delivery error, proceed and enable the email forwarding in Outbound Spam filter policies, by using one of the methods below.
Method 1. Modify Outbound Spam Filter Policy in Office 365 Admin Center.
To modify the default antispam filter settings in Office 365 Admin center:
2. Expand Threat Management on the left pane and click Policy.
3. In Threat Policies click Anti-spam
4. In Anti-spam settings, expand the Outbound spam filter policy and click Edit Policy. *
* Note: If you want to enable the external email forwarding for specific users, proceed to method-2 below.
5. In 'Outbound spam filter policy' settings, set the Automatic Forwarding to On-Forwarding is enabled and click Save.
Method 2. Enable External Forwarding for Individual Users in Office 365.
To enable the email forwarding for certain mailboxes in Office 365 anti-spam settings:
1. In Office 365 antispam filter settings, click Create an outbound policy.
2. Give a Name for the new policy, and then:
a. Set the Automatic Forwarding to On-Forwarding is enabled.
b. Click Add a condition.
c. Select Sender is and then select the users to apply the new outbound policy.
d. Click Save when done.
Method 3. Modify Outbound Spam Filter Policy through PowerShell in Office 365.
To enable the email forwarding in Outbound Spam Filter policy, using PowerShell, give this command: *
Set-HostedOutboundSpamFilterPolicy -Identity Default -AutoForwardingMode On
* Note: The above command, allows the emailing forwarding in outbound spam filter policy named "Default". (source: https://docs.microsoft.com/en-us/powershell/module/exchange/set-hostedoutboundspamfilterpolicy?view=exchange-ps)
That's it! Let me know if this guide has helped you by leaving your comment about your experience. Please like and share this guide to help others.