Please give me help about Eudora and Microsoft Exchange Server

I am having this problem from the time I log on in the exchange server. My Eudora for Mac failed to work with Microsoft Exchange. It says that the POP server has protocol error while checking the mails. I need solutions for this. Please help me resolve my problem.

Task Progress
Error while checking mail for <<Dominant>>:
I said PASS
And then the POP server said: – ERR Protocol error. 16
