EM-3109
Microsoft does not allow sending from this address
Why it happens
Exchange Online refused to send the reply from the chosen address: your account has no Send As permission on that mailbox or address.
What to do
Ask your Microsoft 365 administrator to give your account Send As on the mailbox, or choose another sending address in the email settings, then send the reply again.
- HTTP status
- 422
- Retrying does not help