Remote Server returned ‘550 5.7.708 Service unavailable
Delivery has failed to these recipients or groups:
Your message wasn’t delivered because the recipient’s email provider rejected it.
Diagnostic information for administrators:
I was helping a client with a new 365 Exchange mailbox setup and the email would not deliver. All the DNS records were correct so it was driving me mad trying to figure out what was wrong. I got the error when sending from online or on in Outlook desktop. I logged into their account on browser on my pc and it sent just fine. Culprit had to be Norton. I disabled Norton and both online and Outlook delivered the email just fine.
So that was that, Norton was removed and client was disappointed and happy at the same time. Googling this error didn’t help, so that’s why I posted this. Might help you.
