Hello Christian Thiele,
Did you follow [cache refresh docs](https://gluu.org/docs/gluu-server/4.5/user-management/ldap-sync/)?
Bellow info indicate that about an attribute mapping. Could you check please your attribute mapping source to destination is ok?
>```
2023-09-24 19:38:54,984 DEBUG [qtp1199673596-17] [org.gluu.oxauth.service.common.UserService] (UserService.java:239) - Getting user information from LDAP: attributeName = 'samaccountname', attributeValue = 'test21'
```
Also could you check `oxauth_script.log` if Casa script is responsible for this definitly we get hints why is that. Could you please attached the logs. `oxauth.log` and `oxauth_script.log`
regards~ Mostafejur Rahman