Error: 18456, Severity: 14, State: 11 ?

Hi all,
I granted a Domaingroup rights in a DB.
If users from this AD group try to connect they geting the above mentioned error.
(Login failed for user 'MYDOMAINsomeuser'. Reason: Token-based server access validation failed with an infrastructure error. Check for previous errors. [CLIENT: 172.xx.xxx.xx]
If I grant all of this users individualy (same access rights as the group had) login works all right??
Any help is highly appreciated.
TIA acki4711