Connection timeout

Hello,
Some days ago the sync clients stopped to work with one server.
I have the following servers :

  • A owncloud 10 with nginx
  • B docker official nextcloud 13 image behind nginx reverse proxy
  • C docker official nextcloud 13 image behind nginx reverse proxy

My nextcloud client is connected with the 3 servers
Everything was working some days ago and a bug occured…
The server B stopped syncronizing with my desktop and my android client, The serveur C is working on the same server with similar configuration.

On the desktop client (manjaro 18.0.3).
When i stop the mouse on the bar icon :

Nectcloud : disconnected from accounts: 
Account me@B : network error
Connection timed out

The debug option on NextCloud client shows :

[OCC::FolderMan::slotAccountStateChanged        Account "me@B" disconnected or paused, terminating or descheduling sync folders

The phone file app loads for a long time, and display « No file here »
But the web interface works very well, like the contacts and calendar.

  • I did not upgrade anything the last days

Shoud I get my server to the next version?
There is no logs about failed connections on the container stdout.
If you know how I can troubleshoot this…
Thanks !

Edit:
The command

php occ integrity:check-core

Return an empty result

php occ maintenance:repair

Does not repair webdav

php occ integrity:check-core

Is not checking webdav

UPDATE:
I did upgrade to version 14 then 15.
The desktop and mobile clients cant connect anymore.

  • error 405 when loging in with tocken
  • “access forbidden, invalid reqest” when loging in with username/password

The serveur log only shows 302 or 200 status code…