Can not create or edit files in GitHub

Hello,
I am unable to edit or create files in my GitHub repo from the web client.
It always fails with File could not be edited

I am able to push to my repository using git without issues.
Also this might be related to dependabot not being able to create PRs.
I have 3 outdated dependencies I want to upgrade but. One of the dependencies is failing with:
Invalid git modules config
The others are failing with no specific error message. The issue is, that there is no error in the dependabot log files.

I have a git submodule in this repository. The file structure looks like this:

And my .gitmodules like this:

[submodule "./backend/label"]
	path = backend/label
	url = https://github.com/<org>/<repo>.git
	branch = main

Maybe someone can help me.

Sincerely,
Jan

Okay looks like I finally managed to fix it.
The issue was .backend/label in the .gitmodules file. Apparently you have to omit the dot.
So this works:

[submodule "backend/label"]
	path = backend/label
	url = https://github.com/<org>/<repo>.git
	branch = main

Sincerely,
Jan