502 error with Univention


I had a problem with my server before the lockdown and I was able to restart it only many days ago.

Since the restart, I had a 502 error when I try to reach owncloud. The message is :

502 bad gateway

The proxy server received an invalid response from an upstream server.

Apache/2.4.25 (Univention) Server at furya.ovh Port 443

My setup is :

  • windows 10 as host
  • workstation
  • ucs 4.4 with owncloud image that I downloaded from owncloud site

I can view the Univention pages. I have this error only when I try to go to /ownlcoud.

Is something possible to restart my owncloud without loosing everything ? Or do I need to reinstall ?

How to not loose calendar stuff ? And how to prevent this error ?

Thank for your help.

Server configuration

Operating system: windows 10 with workstation for the host / Univention Corporate Server 4.4-4 errata617 for the image

Web server: Apache 2.4.25


PHP version: 7.0.33-0+deb9u7

ownCloud version: (see ownCloud admin page) can’t access

Updated from an older ownCloud or fresh install: fresh install

Where did you install ownCloud from: ucs 4.4 image

Signing status (ownCloud 9.0 and above): can’t access

The content of config/config.php: I have this error “Could not open input file: occ”

List of activated apps: I have this error “Could not open input file: occ”

Are you using external storage, if yes which one: smb

Are you using encryption: no

Are you using an external user-backend, if yes which one: no one


can you post the docker logs of the ownCloud container?

“docker logs owncloud_owncloud_1” should do the trick.


Thank for your help !

I don’t use docker. I have a ucs VM inside workstation.


i think that the UCS app for ownCloud is using docker internally.


I saw something about univention bug here :

As I don’t have time, I simply reinstal everything.

Hope it can help others !

Thank for your help.

1 Like


it seems the problem originates from a defective UCS update if i’m understanding this blog post correctly and the only way is indeed to reinstall (at least the affected apps):