The error "The SMTP address has no mailbox associated with it" occurs due to an issue with the technical setup of mailboxes in Microsoft 365. You will be unable to send emails from Workable until it is resolved, or the Microsoft 365 integration is disabled.
To resolve the issue, your Microsoft 365 admin (usually a member of the IT team at your company) should follow the troubleshooting steps outlined below:
- Within the Credentials section of the Email Server Profile record, use the UPN format (example: firstname.lastname@example.org) for the User Name instead of the domain\username format.
- If the User Name is in the UPN format and you still encounter this error, verify that a mailbox exists for the user and that the UPN value in the User Name field matches the email address for the user's mailbox in Exchange.
Check the full Microsoft 365 SMTP troubleshooting guide.