Then all users you have specified will be able to enable automatic external forwarding rules in their Microsoft 365 mailboxes. In the Forwarding rules section, select Automatic forwarding rules -> On Forwarding is enabled.Then select the users and/or groups that you want to allow external forwarding.

Create a new anti-spam outbound policy.

This option is more preferable from the security point of view. In our example, we’ll only allow external email forwarding for the specific tenant users or groups. If you want to allow external forwarding for all Microsoft 365 mailboxes, edit the Anti-spam outbound policy (Default). Go to -> Threat Management -> Policy -> Anti-Spam Policy. You can allow automatic email forwarding for the whole organization or specific mailboxes in the Security and Compliance settings of your Microsoft 365 tenant. Please contact your administrator for further assistance. Office 365 received the message that you specified, but couldn't deliver it to the recipient due to the following error:Įrror: ‎550 5.7.520 Access denied, Your organization does not allow external forwarding. You may see the same message when you check the message trace in Microsoft 365.

Remote Server returned '550 5.7.520 Access denied, Your organization does not allow external forwarding. If you create an inbox rule in an Exchange Online mailbox (using Outlook or PowerShell) to automatically forward incoming emails from your mailbox to an external email address, you will see the NDR message when trying to forward an email using the rule: Your message wasn't delivered because the recipient's email provider rejected it.

Create mail forward server