Problem with connecting to Windows Server 2003

[Guest Ashelon]

Hi. I have a server running Win Server 2003, with domain and AD.

 

Occassionally, internal users have been complaining that they cannot access

the shared drive on the server. Whenever they try to access it as a mapped

network drive (which previously worked) or from Network Neighbourhood, it

prompts them for a username and password. Using the same credentials do not

work because the login box will say "The username you typed is the same as

the username you logged in with..."

 

Logging out of windows and logging in again at the client PCs usually solve

the problem, but not always. Whenever they come into the office in the

morning, they usually can access the shared drive. It seems that the problem

appears after several hours of use.

 

What are the possible reasons for this error?