We have Exchange 2003 on Windows Server 2003, two back-end, one front-end server. Approximately 300 mailboxes. All service packs applied.OWA site has been up and running for several years. Lately certain users cannot login to OWA. This problem seems to have to do with group membership for the user . . . if I remove the user from some or all groups (no user is member of more than about 5-6 groups), the problem disappears. These problem users have always been able to login in the past.Did some searching for answer, "inherit permissions" checkbox is selected on all objects. Exchange Servers group is present on top domain object.This occurs w/maybe 10 of 300 users.lisa macdonald

Hi,First please try to post the login failures here for further troubleshooting.Beisdes,pleaseuse NTDSUTIL (group membership evaluation)to check all the groups a user is a member of (even across domains within the forest, even if nested). 1. Logon in normal mode on same DC with an Enteprise Admin account. 2. Execute the following commands from a CMD prompt:NTDSUTILGR ME EVSET AC DC [DCname]SET GL CA [GCname]SET RE DC [ResourceDCname] RUN [domain.com] user Note:Please RUN[domain.com] User(working user) andRUN[domain.com] User(problematic user)3. After that, you can check tsv file from c:\Documents and Settings\user.There please compare the working user and problematic user.Regards,Xiu