Collabora Proxy Error 502


I installed Docker using this manual:
For Collabora I followed this

Yet when I try to use Collabora the nextcloud log shows this error "GuzzleHttp\Exception\ServerException: Server error response [url] [status code] 502 [reason phrase] Proxy Error

I spend some time looking for possible reasons for this but couldn’t find any.
I am using nextcloud 12 with apache and php7 on Debian 8 x64 with Docker 17.03.1-ce, build c6d412e.
The Debian is freshly installed and I only followed the steps in the above mentioned manuals.

When I issue the “docker ps” command in the STATUS column it always shows a value less than a minute.
So I assume that for some reason my docker keeps crashing every few seconds. Or is this the expected behavior and the problem is somewhere else?
If docker is the problem, are there any ways to fix that?

Thank you!

Using the same steps with Ubuntu 16.04 worked flawlessly.
So while not necessarily a good solutions for others with this problem it now works for me.

I have the same problems under Debian actually. I also see that the STATUS up time is 34 seconds while other products are up 2 months.

sudo docker ps                                                                                                                                                    
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS                      NAMES 
ff7bb05494f4        collabora/code      "/bin/sh -c 'bash ..."   12 hours ago        Up 34 seconds>9980/tcp   peaceful_haibt 
5a0be9cc3e04        mquandalle/wekan    "/bin/sh -c 'bash ..."   14 months ago       Up 2 months>80/tcp       wekan_wekan_1 
02cf142a5f3c        mongo               "/ mo..."   14 months ago       Up 2 months         27017/tcp                  wekan_wekandb_1   

I’m using Docker version 17.05.0-ce.