CP loses connectivity with AD controller for login

Has anyone ever had situations with the CP system not able to authenticate user accounts for login, then it’s rectified by restarting the CP server…. and then it happens again a few hours/days later? ?We’ve checked the AD controllers, as well as the CP server itself – no apparent issues are present with anything, this appears to be an issue with CP itself. ?We have no trouble logging into any of the servers in that domain, nor do any Exchange users have problems authenticating.

Scratching my head trying to figure this out. ?Any ideas? ?Thanks!

Rick