Outlook doesn't look up smtp-adresses for some NT usernames
I've a problem with the NT Username to SMTP adress lookup in Outlook and Exchange. For most of the users I can write the NT username and Outlook fills in the SMTP adress in the TO: field. For some users (4 of 450) this doesn't work and I have to write the smpt-adress.
Is this a bug? Anyone with a solution or an idea?