Enable External Forwarding in Microsoft 365

Some Microsoft 365 users might see a problem with receiving their inbound emails in LiveAgent due to a Microsoft's security initiative. When your Microsoft 365 mail account tries to forward your email to your LiveAgent's built-in mail account, instead of a new ticket, you'll get a bounce notification with the following text:

550 5.7.520 Access denied, Your organization does not allow external forwarding. Please contact your administrator for further assistance. AS(7555)

Please contact your Microsoft 365 administrator and ask them to allow automatic external forwarding for any mailboxes you want to connect with LiveAgent using the Forwarding option. This guide should help your administrators find and change the protection policy that is blocking the forwarding. Microsoft's documentation on these settings is found here: Configuring external email forwarding in Microsoft 365.

You may choose to enable automatic forwarding for all your Microsoft 365 mailboxes or enable it only for the mailboxes you're actually forwarding to LiveAgent.

How to enable automatic forwarding for all your Microsoft 365 mailboxes

1. Log in to your Office 365 Security & Compliance portal and go to Threat management->Anti-spamsection.
2. Click the arrow next to Outbound spam filter policy setting and click the Edit policy button.
3. Click the arrow next to Automatic forwarding, then select On - Forwarding is enabled from the dropdown. Click Save.

How to enable automatic forwarding for individual Microsoft 365 mailboxes

1. Log in to your Office 365 Security & Compliance portal and go to Threat management->Anti-spamsection.
2. Click the Create an outbound policy button.
3. Name your new outbound spam filter policy and add some Description, then click the arrow next to Automatic forwarding and select On - Forwarding is enabled from the dropdown.
4. Click the arrow next to Applied to and then the Add a condition button. From the dropdown list select the Sender is condition, then click in the Add a tag field to add the mailbox(es) for which you'd like to allow the automatic forwarding. Once you have all mailboxes added click Save.

Now you should be able to use the Forwarding option with your Microsoft 365 mailboxes however if it still shouldn't work then there still might be other transport rules or spam policies in place at Microsoft 365 that block external forwarding. If automatic external forwarding is still blocked after adjusting the policies covered about, you should contact Microsoft 365 support for assistance in finding any further blocking that has been set up in your Microsoft 365 account.