Can't sign with users authenticated by ldap

I'm not able to use LibreSign. I get follwowing error:

{"reqId":"7CkTba4Ysuq4YMePkf7w","level":0,"time":"2025-03-12T10:04:14+00:00","remoteAddr":"xxx.xxx.xxx.xxx","user":"denis","app":"user_ldap","method":"POST","url":"/ocs/v2.php/apps/libresign/api/v1/sign/uuid/2b85b21e-ab2e-4fc4-a834-889e83f6edc9","message":"LDAP error No such object (32) after calling ldap_read","userAgent":"Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/134.0.0.0 Safari/537.36","version":"30.0.6.2","data":{"app":"user_ldap"}}

All users and groups are authenticated by ldap_plugin.

When I get the request to sign a document then the assigning the signature will not be finnished.

I double checke the dependencies in the settings as nextcloud admin:

success | Java version: openjdk version "21.0.6" 2025-01-21 LTS | java |  
success | Java binary: /var/www/nextcloud/data/appdata_oczima36cjhb/libresign/x86_64/linux/java/jdk-21.0.6+7-jre/bin/java | java |  
success | PDFtk version: 3.3.3 | pdftk |  
success | PDFtk path: /var/www/nextcloud/data//appdata_oczima36cjhb/libresign/x86_64/pdftk/pdftk.jar | pdftk |  
success | JSignPdf version: 2.3.0 | jsignpdf |  
success | JSignPdf path: /var/www/nextcloud/data/appdata_oczima36cjhb/libresign/x86_64/jsignpdf/jsignpdf-2.3.0/JSignPdf.jar | jsignpdf |  
success | pdfsig version: 22.12.0 | pdfsig |  
success | pdfinfo version: 22.12.0 | pdfinfo |  
success | Root certificate setup is working fine. | openssl-configure

It seems that there is something wrong with ldap users.

Start by reproducing the POST request to /ocs/v2.php/apps/libresign/api/v1/sign/uuid/... with an LDAP-authenticated user and compare it with a local user. Investigate the reported user_ldap “No such object (32)” error during signature assignment and verify the documented dependency setup. Done means LDAP-authenticated users can complete signing without this error.