We have set up a new Exchange server in our enterprise to handle emails to and from our help desk application. the SMTP side is working fine however I am unable to authenticate on the POP side. I can see the logon attempt when I look at current sessions in my default POP server however its kicking it back. Its looking like it might be somewhere between exchange and the AD but everything I have checked so far looks good. Does anyone have any thoughts or has anyone had a similar problem?