LDAP Contacts Backend - copy to address book

Hi there,
when I search for a user in the LDAP it is displayed in the search window. If I tap the “Copy to address book” icon, an internal server error appears:

Interner Serverfehler
Der Server konnte die Anfrage nicht fertig stellen.
Sollte dies erneut auftreten, sende bitte die nachfolgenden technischen Einzelheiten an Deinen Server-Administrator.
Weitere Details können im Server-Protokoll gefunden werden.
Technische Details
    Entfernte Adresse: 192.168.30.67
    YgpYM23ECF3WEyW2N6r4

I see the following information in the nextcloud.log

"2021-09-30T09:34:52+00:00","remoteAddr":"192.168.30.67","user":"Administrator","app":"files_sharing","method":"GET","url":"/index.php/apps/ldap_contacts_backend/import/0/dWlkPWZ5bm4uaGFyYmljaCxvdT11c2VycyxkYz1oYXJuZXQsZGM9ZGU=?requesttoken=I/XMJxaTRAJ4ZJcBhT0VHeHL0twz3hTgeOq0kxBiumA%3D:UaW7YGDrF1QzPvgqsEdRVoqNmu9VqHrRCdnZ20cg%2BSo%3D","message":"/appinfo/app.php is deprecated, use \\OCP\\AppFramework\\Bootstrap\\IBootstrap on the application class instead.","userAgent":"Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:92.0) Gecko/20100101 Firefox/92.0","version":"22.1.1.2"}
{"reqId":"YgpYM23ECF3WEyW2N6r4","level":3,"time":"2021-09-30T09:34:52+00:00","remoteAddr":"192.168.30.67","user":"Administrator","app":"index","method":"GET","url":"/index.php/apps/ldap_contacts_backend/import/0/dWlkPWZ5bm4uaGFyYmljaCxvdT11c2VycyxkYz1oYXJuZXQsZGM9ZGU=?requesttoken=I/XMJxaTRAJ4ZJcBhT0VHeHL0twz3hTgeOq0kxBiumA%3D:UaW7YGDrF1QzPvgqsEdRVoqNmu9VqHrRCdnZ20cg%2BSo%3D","message":"Could not complete search with dn \"uid=fynn.harbich,ou=users,dc=example,dc=com\", query \"\" and filters \"*\". LDAP error was [2] Protocol error.","userAgent":"Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:92.0) Gecko/20100101 Firefox/92.0","version":"22.1.1.2","exception":{"Exception":"Symfony\\Component\\Ldap\\Exception\\LdapException","Message":"Could not complete search with dn \"uid=fynn.harbich,ou=users,dc=example,dc=com\", query \"\" and filters \"*\". LDAP error was [2] Protocol error.","Code":0,"Trace":[{"file":"/var/www/html/nextcloud/apps/ldap_contacts_backend/lib/Service/LdapQuerent.php","line":56,"function":"execute","class":"Symfony\\Component\\Ldap\\Adapter\\ExtLdap\\Query","type":"->","args":[]},{"file":"/var/www/html/nextcloud/apps/ldap_contacts_backend/lib/Service/LdapCardBackend.php","line":56,"function":"fetchOne","class":"OCA\\LDAPContactsBackend\\Service\\LdapQuerent","type":"->","args":["uid=fynn.harbich,ou=users,dc=example,dc=com"]},{"file":"/var/www/html/nextcloud/apps/ldap_contacts_backend/lib/Service/AddressBook.php","line":59,"function":"getCard","class":"OCA\\LDAPContactsBackend\\Service\\LdapCardBackend","type":"->","args":["dWlkPWZ5bm4uaGFyYmljaCxvdT11c2VycyxkYz1oYXJuZXQsZGM9ZGU="]},{"file":"/var/www/html/nextcloud/apps/ldap_contacts_backend/lib/Controller/ContactsController.php","line":89,"function":"getChild","class":"OCA\\LDAPContactsBackend\\Service\\AddressBook","type":"->","args":["dWlkPWZ5bm4uaGFyYmljaCxvdT11c2VycyxkYz1oYXJuZXQsZGM9ZGU="]},{"file":"/var/www/html/nextcloud/lib/private/AppFramework/Http/Dispatcher.php","line":217,"function":"import","class":"OCA\\LDAPContactsBackend\\Controller\\ContactsController","type":"->","args":[0,"dWlkPWZ5bm4uaGFyYmljaCxvdT11c2VycyxkYz1oYXJuZXQsZGM9ZGU="]},{"file":"/var/www/html/nextcloud/lib/private/AppFramework/Http/Dispatcher.php","line":126,"function":"executeController","class":"OC\\AppFramework\\Http\\Dispatcher","type":"->","args":[{"__class__":"OCA\\LDAPContactsBackend\\Controller\\ContactsController"},"import"]},{"file":"/var/www/html/nextcloud/lib/private/AppFramework/App.php","line":156,"function":"dispatch","class":"OC\\AppFramework\\Http\\Dispatcher","type":"->","args":[{"__class__":"OCA\\LDAPContactsBackend\\Controller\\ContactsController"},"import"]},{"file":"/var/www/html/nextcloud/lib/private/Route/Router.php","line":301,"function":"main","class":"OC\\AppFramework\\App","type":"::","args":["OCA\\LDAPContactsBackend\\Controller\\ContactsController","import",{"__class__":"OC\\AppFramework\\DependencyInjection\\DIContainer"},{"sourceId":"0","contactId":"dWlkPWZ5bm4uaGFyYmljaCxvdT11c2VycyxkYz1oYXJuZXQsZGM9ZGU=","_route":"ldap_contacts_backend.contacts.import"}]},{"file":"/var/www/html/nextcloud/lib/base.php","line":1000,"function":"match","class":"OC\\Route\\Router","type":"->","args":["/apps/ldap_contacts_backend/import/0/dWlkPWZ5bm4uaGFyYmljaCxvdT11c2VycyxkYz1oYXJuZXQsZGM9ZGU="]},{"file":"/var/www/html/nextcloud/index.php","line":36,"function":"handleRequest","class":"OC","type":"::","args":[]}],"File":"/var/www/html/nextcloud/apps/ldap_contacts_backend/vendor/symfony/ldap/Adapter/ExtLdap/Query.php","Line":126,"CustomMessage":"--"}}

Here is my ldap_contacts list

root@dsme01:/var/www/html/nextcloud# sudo -u www-data php occ ldap_contacts:list
id: 0
addressBookDisplayName: Harbich
host: ldap.intern.example.com
port: 636
agentDn: CN=admin,DC=example,DC=com
agentPassword: #############
bases:
  DC=example,DC=com
searchAttributes:
  UID
attributeMapping:
tEnc: ssl
filter: 

Do you have a tip for me?

Greetings from Stefan Harbich