User LDAP app not showing tabs / not working


I am using latest NC release 16.0.4 and I want to connect to SLAPD. After activating the user_ldap app in admin preferences / apps I go to the user ldap preferences.

I can enter values, but none are stored. Also the preferences section is not showing any tabs.

I have created a config with php occ commands but that is also not working and I cannot connect to the SLAPD server.

I have checked connection with ldapsearch which has success.

Any idea / help?

Regards, Dietmar