Git push - remote: fatal: not a git repository: '.'

Question

I am currently running into an issue, when trying to push my changes to origin I am getting this error:

Enumerating objects: 7, done.
Counting objects: 100% (7/7), done.
Delta compression using up to 8 threads
Compressing objects: 100% (4/4), done.
Writing objects: 100% (4/4), 4.84 KiB | 2.42 MiB/s, done.
Total 4 (delta 3), reused 1 (delta 0), pack-reused 0
remote: fatal: not a git repository: '.'
error: remote unpack failed: unpack-objects abnormal exit
To ///DIRECTORY
 ! [remote rejected]     TEST -> TEST (unpacker error)
error: failed to push some refs to '///DIRECTORY'

Pull is working perfektly fine. I only get this error, when I try to push my commits, while working from home. In the office, connected via LAN everything works. I tried it with a mobile hotspot but still no luck.

I tried

git init

also

git gc --aggressive --prune

i also tried to add the remote under another name with

git remote add --mirror=push NEW //DIRECTORY

git remote -v showed the path correctly. I also have read and write permission for the remote, i checked it several times.