I wanted to try to solve the problem directly in the database. I read that the fields had to be empty when you clicked on save (How to install ONLYOFFICE in Nextcloud Hub and new integration feature). So I thought I would uninstall the plugins, delete the configuration of the fields where I have problems with it, and reinstall the plugins.
Unfortunately it didn’t work either:
sudo -u www-data php /var/www/nextcloud/occ app:remove documentserver_community
sudo -u www-data php /var/www/nextcloud/occ app:remove onlyoffice
update public.appconfig set configvalue = '' where configkey = 'jwt_secret' ;
update public.appconfig set configvalue = '' where configkey = 'DocumentServerUrl' ;
root@box:~ # sudo -u www-data php /var/www/nextcloud/occ app:install
documentserver_community && sudo -u www-data php /var/www/nextcloud/occ app:install onlyoffice
documentserver_community installed
documentserver_community enabled
onlyoffice installed
onlyoffice enabled