Nextcloud service is not starting - jitsi and router seem to work fine

First of all, thanks for this awesome repo!
I have some issues with the nextcloud instance, maybe anyone with more experience can help?

I want to install a nextcloud and jitsi instance on my Zotac zbox CA621 nano with 16GB RAM and 265GB SSD behind a Fritzbox.
I registered 3 (free) subdomains from noip.com (*.ddns.net) and pointed them to the IP of my Fritzbox, which has a portforwarding to the zbox. I installed Ubuntu Server 20.04 LTS performed updates and cloned the repo.
I then followed the instructions and ended up having a running router and jitsi server. However the Nextcloud instance is not running. I set up name and domain as for the others, but the Let's Encrypt Cert is missing. When I open the nextcloud adress in Firefox and confirm the security exception for missing https, the page simply contains: "404 page not found".

Where could I have made a mistake?

Edit:
I found sth in the events log. Potentially, it doesn't like the values I set?

`$ kubectl get pods`
```
NAME READY STATUS RESTARTS AGE
nextcloud-team-nextcloud-db-64d687b6f9-t6b8p 0/1 Pending 0 25h
nextcloud-team-nextcloud-nc-69f7654bf-jc8r6 0/2 Pending 0 25h
video-team-video-jvb-559b8f7585-6cxqq 1/1 Running 1 25h
svclb-traefik-zxz2l 2/2 Running 2 22h
video-team-video-jicofo-587b7c8c8b-9z97x 1/1 Running 1 25h
nextcloud-team-nextcloud-redis-86d7f4ffff-jhkgc 1/1 Running 1 25h
traefik-6bc99d5778-d477v 1/1 Running 1 22h
landingpage-5d8dc7cd5c-jvtvf 1/1 Running 1 22h
video-team-video-web-6655f6fff4-8jxp7 1/1 Running 1 25h
video-team-video-prosody-6769ff54d7-7tt8c 0/1 CrashLoopBackOff 129 25h
```
`$ kubectl get events`
```
LAST SEEN TYPE REASON OBJECT MESSAGE
Warning FailedScheduling pod/nextcloud-team-nextcloud-nc-69f7654bf-jc8r6 persistentvolumeclaim "nextcloud-team-nextcloud-nc-data" not found
Warning FailedScheduling pod/nextcloud-team-nextcloud-db-64d687b6f9-t6b8p persistentvolumeclaim "nextcloud-team-nextcloud-nc-db" not found
10m Warning FailedPostStartHook pod/video-team-video-prosody-6769ff54d7-7tt8c Exec lifecycle hook ([/bin/bash -c sleep 60; prosodyctl --config /config/prosody.cfg.lua register meetmaster jitsisubdomain.ddns.net password]) for Container "prosody" in Pod "video-team-video-prosody-6769ff54d7-7tt8c_default(8208a497-f090-40e7-9101-25ce7aaba746)" failed - error: command '/bin/bash -c sleep 60; prosodyctl --config /config/prosody.cfg.lua register meetmaster jitsisubdomain.ddns.net password' exited with 1: , message: "Error: Account creation/modification not supported.\n"
5m39s Normal Pulled pod/video-team-video-prosody-6769ff54d7-7tt8c Container image "jitsi/prosody" already present on machine
51s Warning BackOff pod/video-team-video-prosody-6769ff54d7-7tt8c Back-off restarting failed container

```

Start by reproducing the deployment and running `kubectl get pods` and `kubectl get events`, as shown in the issue. Trace the Nextcloud pod scheduling messages and the related deployment configuration; done means the Nextcloud database and application pods become ready, the certificate is present, and the domain no longer returns a 404.

Written by the indexing model from the issue text.