The contents of the support template would be a good start. ![]()
Nearly all of those errors appear to be because your instance is unable to connect back to itself.
The url in overwrite.cli.url in your Nextcloud config (as well as trusted_domains) are utilized for the setup checks.
So check:
- the values there
- whether your Nextcloud container can connect to its own URL (by running
curlor similar from the command line in the container)