One of our customers added a new user in AD and received NRDs for messages sent to that user. His account was also not able to log in through OWA.
When checking AD we found that his SMTP address was created, the X400 address for his account was not.
After checking ESM, his name did not show up in the list of mailboxes, so we attempted to delete and recreate the mailbox, and this time neither the SMTP or X400 were created.
We added the SMTP address manually, but are having no luck with the X400.
Our customer suggested deleting his AD account altogether and starting over, but there must be something else I can try.