Login Attempt Limit Reached: The error logs indicate that the login attempts from the IP address have reached the limit, resulting in a captcha requirement. This can happen due to multiple failed login attempts. To resolve this, ensure that proper email and credentials are being used for the user jochen@example.com.
You can also set a contact email for this user jochen@example.com as below in the admin panel, the contact email can be used for login.
Then you can reset password for that user to a simple one and try again.
In your log, you have Invalid File ID Error. But this is not related to the login issue as the time for this error log is far apart from the error log for login failing.