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Unblock email forwarding on MS365 mailboxes

Configure email forwarding

It is possible to set up an email transfer with an Exchange Online mailbox to an external SMTP address from the administration portal

A user can also set up a transfer independently using the options in the webmail:

It’s never recommended to use mail transfers, but in migration contexts, it’s often necessary.

The mail transfer works without problem, because unlike the default configuration of Exchange On-premise, the mail transfer is allowed by default on the remote domains default policy. You can disable this feature globally and enable it only for specific domains by declaring remote domains with AutoForwardEnabled=$true.

Configure antispam to avoid error 550 5.7.520

However, sometimes internal mailboxes cannot send emails to mailbox that configured with an email transfer and the error message is as follows: 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)

To correct this problem, access to the anti-spam configuration page of MS365 using the following URL:

You have to look at the configuration of the “Anti-spam outbound policy (default)”.

To correct the problem, one solution is to set up the “Automatic forwaring” setting into “On – Forwarding is enabled.”

The mall transfer will then be functional as well for emails coming from external senders and from internal senders.

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