Hi All,
We are experiencing the same problem below but I don't know how to solve it in Exchange 2013.
We have an employee that is restarting his position with our company. His account was removed when he left years ago but had a contact with the email address first.last@company.us . I deleted that contact and set him up a new AD and email account. I have his account setup as the first.last@company.us, but I keep getting
"The e-mail address you entered couldn't be found. Please check the recipient's e-mail address and try to resend the message. If the problem continues, please contact your helpdesk."
I checked and the email address is listed in email addresses. One of the Alias email addresses work fine, but the one that is on his cards (the one above) does not. Any ideas?