I don't know if i am posting in the proper forum,, if i did am sorry if not then am not sorry...

I have a business e-mail account which is a property to my business. Sometimes when the log on process completes the following message displays instead of my Inbox:
"An internal error occured. Please try again later and contact your ISP if the problem persists."

The problem is that when one of my colleagues log out, the process completes successfully, later when i try to access my account, the server tends to display his inbox{Just the From, Subject, Date information} When clicking on a message the previous message displayes again.

Any notions why? This really sucks, i get so upset from this, please help!

N.B. The website and the e-mail system has been designed by ASP.