The message hasn't been delivered because it's stuck in a forwarding loop. The intended recipient of the message can check ...

The message hasn't been delivered because it's stuck in a forwarding loop. The intended recipient of the message can check for forwarding settings using the following steps:
1.Sign in to Outlook on the web.
2.Select Settings > Your app settings > Mail > Accounts > Forwarding.
If forwarding is on, the forwarding email address will be displayed.
3.To turn off forwarding, select Stop forwarding, and then save any changes.
If forwarding is already turned off, there is probably an Inbox rule forwarding email to the different email address.