If I change Settings "Timetracking mode" no Start/Stop possible

[Spacetracer]

I use Kimai on Windows 10 with Docker 20.10.7 and Kimai 1.14.1 stable (Ayumi).
If I change Settings "Timetracking mode" to "[Time-clock] user can start and stop records, but not edit the times or duration",
kemai wont start Timetracking.
Docker CLI shows the follow message after pressing start button:
localhost:8001 172.17.0.1 - - [09/Aug/2021:14:48:54 +0100] "POST /api/timesheets HTTP/1.1" 400 644 "-" "Mozilla/5.0"
With default Settings:
localhost:8001 172.17.0.1 - - [09/Aug/2021:14:54:24 +0100] "POST /api/timesheets HTTP/1.1" 200 726 "-" "Mozilla/5.0"