Letsencrypt Renew-Problem

[Former user]

When I try to renew the Letsencrypt-Certificate the following error is shown 2018-03-14 19:53:26] LEScript.INFO: Account already registered. Continuing. [2018-03-14 19:53:26] LEScript.INFO: Starting certificate generation process for domains [2018-03-14 19:53:26] LEScript.INFO: Requesting challenge for mail.wklsoft.de [2018-03-14 19:53:26] LEScript.INFO: Sending signed request to /acme/new-authz [2018-03-14 19:53:27] LEScript.INFO: Got challenge token for mail.wklsoft.de [2018-03-14 19:53:27] LEScript.INFO: Token for mail.wklsoft.de saved at /opt/www//.well-known/acme-challenge/yGCLwOHeqPP3iUJZ6WwZEF0iWyBcGR7wbrL-jVR5yEk and should be available at http://mail.wklsoft.de/.well-known/acme-challenge/yGCLwOHeqPP3iUJZ6WwZEF0iWyBcGR7wbrL-jVR5yEk [2018-03-14 19:53:27] LEScript.ERROR: Please check http://mail.wklsoft.de/.well-known/acme-challenge/yGCLwOHeqPP3iUJZ6WwZEF0iWyBcGR7wbrL-jVR5yEk - token not available [2018-03-14 19:53:27] LEScript.ERROR: #0 /opt/admin/src/Analogic/LetsEncryptBundle/Handler/LeHandler.php(55): Analogic\ACME\Lescript->signDomains(Array)

The challenge couldn't loaded from http://mail.wklsoft.de/.well-known/acme-challenge/yGCLwOHeqPP3iUJZ6WwZEF0iWyBcGR7wbrL-jVR5yEk because the file is not created. When I go into the container I can create a file in the folder. But something goes wrong when the Script tries to create the file. There is no other error. Is there another log?

[Wolfgang Klaus]

Problem is solved. Directory /opt/www/.well-known is mounted in container. But user www-data has no rights to write in directory. Log found in data/log/php7.1-fpm.log