we have several generic mailboxes and grant full access to users using security groups. Normally this works fine but sometimes when I add a new user he cannot expand the folders of this mailbox although he is member of the security group. Waiting some hours doesn´t help.
However, when the username is added directly with full access it starts working immediately for him.
To me this looks like there is a temporary problem with group resolution in AD. But I haven´t found any errors and if it once works for a user it works always. Vice versa, if it doesn´t work for a user from the beginning it never works even if I try to add this mailbox to his Outlook several times.
Any hint is welcome - thanks!