OpenProject 13.3.0 reports error 500 after App upgrade on UCS 5.0-6 errata962

Dear UCS community,

My setup concerns an UCS 5.0-6 errata962 with the OpenProject App 13.3.0 installes in a docker container via the App Center. While the previous versions of the OpenProject App worked fine over quite a long time, I cannot reach OpenProject any longer due to an Error 500 shown as soon as the OpenProject URL is invoked.

Below please find the Apache2 log files from the OpenProject App running in the docker container:

root@ucs:~# univention-app shell openproject
root@openp-53053044:/app# tail -f /var/log/apache2/other_vhosts_access.log
_default_:80 - - [25/Feb/2024:13:10:03 +0100] "GET /openproject/ HTTP/1.1" 302 1448 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/16.6 Safari/605.1.15"
_default_:80 - - [25/Feb/2024:13:10:03 +0100] "GET /openproject/login?back_url=https%3A%2F%2F<ucshostname>%2Fopenproject%2F HTTP/1.1" 500 4248 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/16.6 Safari/605.1.15"
_default_:80 - - [25/Feb/2024:13:10:04 +0100] "GET /openproject/api/v3/configuration HTTP/1.1" 304 1118 "https://<ucshostname>/openproject/login?back_url=https%3A%2F%2F<ucshostname>%2Fopenproject%2F" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/16.6 Safari/605.1.15"

root@ucs:~# univention-app shell openproject
root@openp-53053044:/app# cat /var/log/apache2/error.log
AH00558: apache2: Could not reliably determine the server's fully qualified domain name, using Set the 'ServerName' directive globally to suppress this message
[Sat Feb 24 03:22:34.461886 2024] [mpm_event:notice] [pid 87:tid 140457512697152] AH00489: Apache/2.4.56 (Debian) configured -- resuming normal operations
[Sat Feb 24 03:22:34.462198 2024] [core:notice] [pid 87:tid 140457512697152] AH00094: Command line: '/usr/sbin/apache2 -D FOREGROUND'
[Sat Feb 24 03:22:34.698977 2024] [proxy:error] [pid 98:tid 140457501894400] (111)Connection refused: AH00957: http: attempt to connect to ( failed
[Sat Feb 24 03:22:34.699116 2024] [proxy_http:error] [pid 98:tid 140457501894400] [client] AH01114: HTTP: failed to make connection to backend:

As you will notice, the time stamp of the error.log information does not match the access log. It takes quite a whiole until the error.log is written. I realized that the error output remains stable, therefore I did not consider it useful to wait until the latest portion is shown in the errror.log.

Here are some background information related to UCS and OpenProject:

root@ucs:~# univention-app info
UCS: 5.0-6 errata962
Installed: collabora= letsencrypt=2.0.0-2 mailserver=12.0 openproject=13.3.0 samba4=4.16 4.4/guacamole=0.9.13-univention15

root@ucs:~# docker ps --all
CONTAINER ID        IMAGE                                                                   COMMAND                  CREATED             STATUS              PORTS                             NAMES
644cbca41267                        "./docker/prod/entry…"   2 days ago          Up 13 minutes       5432/tcp,>80/tcp   practical_brahmagupta
3504b5f80524                       "/bin/sh -c 'bash st…"   5 weeks ago         Up 9 hours>9980/tcp            recursing_sinoussi
53628ee811ac   "/opt/guacamole/bin/…"   22 months ago       Up 9 hours>8080/tcp           guacamole_guacamole_1
7b0e8eafd334       "/usr/local/sbin/gua…"   22 months ago       Up 9 hours          4822/tcp                          guacamole_guacd_1

root@sucs:~# ucr search --brief appcenter/apps/openproject/
appcenter/apps/openproject/container: 644cbca41267211eb554c572c14ca07c7fc46484e0adc8ddf14a6b7febe6afa5
appcenter/apps/openproject/hostdn: cn=openp-53053044,cn=memberserver,cn=computers,dc=<ucsdomain>,dc=<ucscountry>
appcenter/apps/openproject/ports/80: 40002
appcenter/apps/openproject/status: installed
appcenter/apps/openproject/ucs: 5.0
appcenter/apps/openproject/version: 13.3.0

root@ucs:~# lsof -PniTCP:40002 -sTCP:LISTEN
docker-pr 1969 root    4u  IPv6 1971748      0t0  TCP *:40002 (LISTEN)

root@ucs:~# univention-check-templates
WARNING: The following UCR files are modified locally.
Updated versions will be named FILENAME.dpkg-*.
The files should be checked for differences.


Does anybody has a hint as how to further proceed to identify the problem behind?

Thanks a lot,

In the mean time, I found out as how to obtain a log file. More detailed information is posted here.