Cannot enable apps through UI in 28.0.4 #2193

Image tag

nextcloud:28.0.4-fpm-alpine

Problem

When trying to activate any app on Nextcloud's apps page, the following error appears:

Error: This app cannot be enabled because it makes the server unstable

A Content Security Policy error is logged in the console of the browser.

Refused to connect to 'http://localhost/apps/files/' because it violates the following Content Security Policy directive: "connect-src 'self'".

Reproduction steps / Setup

• Check-out the repository and change to the tests folder.
  https://github.com/te-online/timemanager/tree/main/tests
• Copy the .env.example to .env and add some values for the variables.
• Change the image tag of the app container to the latest
• Run docker-compose up -d, followed by docker exec $(docker ps -qf "name=app") sh -c 'chown www-data:root custom_apps'.
• Navigate to localhost:8000 and try to activate any apps

At this point, I believe this is an issue with the configuration in this image, but it may also just be my proxy configuration that is messing with things. Apologies, if it's user error, but this config has been working for a long time.

I think it unlikely that it's a core server issue, because then it would likely have been caught in RC, this is why I open the issue here.

Background: I use this as my dev and testing setup and I can see some people on Reddit having the same issue, though they don't specify if they're using this container.