Office 365 successfully sent the message to the following external address: {Recipient} If the recipient can't find the message ...

Office 365 successfully sent the message to the following external address:

{Recipient}

If the recipient can't find the message in their Inbox folder, one of several things could have happened:
  1. The message might have been delivered to another folder (for example the Junk Email folder). Ask the recipient to search for the message across all folders in their mailbox.
  2. The recipient might have created a forwarding rule that forwarded the message to a different email address.
  3. There might be something wrong with the recipient's email system.


Until the problem is resolved, try contacting them another way. For instance, send the message to a different email address.