AD Groups Filter not working.

Hi all,

i have a new SRA 1600 with 8.1.0.2-14sv and use a Domain with Active Directory Authentication. It works perfect, but now i need more security with AD Groups filter. Ok, i added a Group in the Users > Local Groups > Edit Local Group 'Demo' (i get the group name with a drop down field, so the connections works perfect) but if i try to login i get the message "Login failed - no suitable group found". I am 100 percent sure that the group in the AD is ok. This is in the logs:

User login failed
Login failed - no suitable group found
LDAP search error code 1, Operations error and will try the partial LDAP entries.

Can someone help?

Thanks, Sven