I have a new exchange online account. I have connected it with the 3 or 4 other email accounts that I manage on 2 separate domains. When I try to send an email to anyone on those two domains I am getting a failure to deliver message:
Delivery has failed to these recipients or groups:
user@domainname
The email address you entered couldn't be found. Please check the recipient's email address and try to resend the message. If the problem continues, please contact your helpdesk.
Diagnostic information for administrators:
Generating server: BY2PR01MB043.prod.exchangelabs.com
user@domainname
Remote Server returned '550 5.1.1 RESOLVER.ADR.RecipNotFound; not found'
The above user however is a valid user at our company and certainly has a valid email address. In fact, I can't seem to send any email to any recipient *in* either of the two domains I have email addresses connected.