git: "pack has bad object" when pushing to remote

I have a bare git repository on my Raspberry Pi which only I use. When pushing to it today, I got this error message:

Counting objects: 460, done.
Delta compression using up to 8 threads.
Compressing objects: 100% (367/367), done.
remote: fatal: pack has bad object at offset 1641: inflate retued -5
error: pack-objects died of signal 13
error: failed to push some refs to 'ssh://christoph@111.111.111.111/media/christoph/afacc396-ec79-4920-9105-513ca4616c06/git/Documents'

As you can see, the repository is accessed via ssh. (I changed the IP address.)

I tried several times but got the same error (even with the same numbers). Then I decided to create a new repository by deleting the folder of the old one, creating a folder with the same name, and executing git init --bare inside it.

Now I get this error when pushing to it:

Counting objects: 3129, done.
Delta compression using up to 8 threads.
Compressing objects: 100% (2265/2265), done.
remote: fatal: pack has bad object at offset 426983445: inflate retued -5
error: pack-objects died of signal 13
error: failed to push some refs to 'ssh://christoph@111.111.111.111/media/christoph/afacc396-ec79-4920-9105-513ca4616c06/git/Documents'

What is the problem and how do I get it to work again?