Running Win2003 SBS server. Yes it's EOL but that's as far as the client wants to go at the moment.
Had some problems with an earlier question regarding one user not being able to authenticate via POP3. Solved that by deleting and recreating user with different username and was able to "Reconnect" the mail box to the new account. That worked well for a while then the user credentials failed once again.
This time when I attempted the same procedure the AD selector window "Select a new user for this mailbox" only lists the "Other objects" not any of the AD users. Attached is a screen capture of the selector screen.
I'm thinking that there may be some AD corruption going on and am at a loss as to the next step to correct this.