We have Azure Devops 2019 on premise. There is Team Project with default team containing user from another domain. The user is also in contributers group.
When this user is selected and saved in AssignTo of a work item, we expect user to receive email, but no such email is received. Email is received when user is in the same domain. Email is received for the user in the different domain, only when explicitly entered in SendTo upon clicking email button.
There is no trace of email that's sent in the exchange server OWA, for the tfsservice user from which emails are sent. Would appreciate advise how to monitor email created and sent, and how to resolve the problem.