Any commit fails with invalid header value

I just installed gitea on a kubernetes cluster and created my first user and repo.
When I want to add a file (or make any changes to the contents of the repo) I get the following message:
The change was rejected by the server with the following message:
Gitea: Internal Server Error
Unable to contact gitea: Post net/http: invalid header field value “Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJuYmYiOjE1ODk0NTE3OTh9.bCeUdsVBTjJAkqL4RdQvSIhxpeLKk6ybzxokMXDb1Co\n” for key Authorization
Please check githooks.
Not sure what could cause this. It is the latest version of gitea.

Thanks in advance! Kristof

Yup, I’ve got that, too: