Collabora on Plesk


I’m on Plesk Onyx 17.5.3 with ubuntu 14.04. I installed nexcloud version 12.0.2 on my server on with a lets encrypt certificate. No problem at that level.
I created a subdomain, also configured with a lets encrypt certificate.
I installed the bluedart / collabora container, which is a modified version of collabora / code by following the installation instructions carefully. Https://
When I want to edit a document in nexcloud, I have the following error: Error while handling socket for socket # 18 in websrv_poll: error: 14094418: SSL routines: ssl3_read_bytes: tlsv1

Does that talk to someone?