[keycloak-user] LDAP username mapping from active directory fails

Hello, i created a new ldap federation in the keycloak settings and imported all users. The thing is that the username attribute was mapped to the ldap cn attribute whereas the username in active directory is sAMAccountName. Therefore i changed the ldapAttribute to that. Now when i go to my ldap settings page and click on "Synchronize" the users fail to update and i am getting this error: 13:31:53,899 ERROR [org.keycloak.federation.ldap.LDAPFederationProviderFactory] (default task-25) Failed during import user from LDAP: org.keycloak.mo dels.ModelException: User returned from LDAP has null username! Check configuration of your LDAP mappings. Mapped username LDAP attribute: cn, user DN : CN=internal2 lastname,OU=DTPH,DC=dls,DC=lan, attributes from LDAP: {whenChanged=[20160217110433.0Z], whenCreated=[20160217110433.0Z], sAMAccountName =[internal2], givenName=[internal2], sn=[lastname], userAccountControl=[512], pwdLastSet=[131001806735067575]} If u put it back to cn it works, but i want to use sAMAccountName for the username. Why does this happen ?