Can´t delete user

When using command:
sudo docker exec -it vikunja-api-1 /app/vikunja/vikunja user delete 4 --now
I get this error, why?
Error removing the user: Default project cannot be deleted [ProjectID: 18]

Thank you

Well you get the error because your user has a default project set. This is already fixed but not yet released as a version, only in unstable builds. You can unset the default project in the user settings and should be able to remove the user then. The other option would be to switch to the unstable build.

I can confirm that the first advice did not work so i might try to use the unstable version. Thank you.