AUDI email issues

[bdtprez]

Since a few days ago when AUDI underwent maitenence, many of my users have been having trouble sending mail. For most of them, having them change their Outlook settings to "My Outgoing Server Requires Authentication" has solved the problem, however several others are still unable to send. I have set up the accounts that werent working on my machine and everything functions fine, however several different customers at different locations using different ISP's are still unable to send mail. Does anyone have a clue what's going on or is anyone experiencing similar problems with AUDI? Any help is appreciated.