I tried to create the new email with firstname.lastname@example.org.It is showing update the mail name properties:mailmng failed: MEAOPO.Mailbox.AddMailbox failed for name=xxxx and domain yourdomain.com [yourdomain].I found there is not email id with the same name.
CAUSE AND RESOLUTION:
The email address was already created longback.Unfortunalty that was deleted.But copy of the same email account still exist in the server mail enable.
1.Log in to the server via RDP and open the mail enable service.
2.Expand the postoffices.
3.Select the domain and open the mail boxes folder.
4.From here delete the existing email id.
5.Restart the mail enable service.
6.Now try to create the email account with the same name..