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. Until it is resolved or the Microsoft 365 integration is disabled, you will not be able to send emails from Workable.
To resolve the issue, your Microsoft 365 admin (usually a member of your company’s IT team) should follow the troubleshooting steps outlined below:
- Within the Credentials section of the Email Server Profile record, use the UPN format (example: user@domain.com) for the User Name instead of the domain\username format.
- If the User Name is already in UPN format and you still encounter this error, verify that a mailbox exists for the user and ensure that the UPN value in the User Name field matches the email address associated with the user’s mailbox in Exchange.
Check the full Microsoft 365 SMTP troubleshooting guide.