sorry, but I can’t help you. Did you figured out some steps to fix the problem. As you can read in my thread I encountered the same problem:
Mär 22 14:01:33 work vikunja[29110]: time=2026-03-22T14:01:33.413+01:00 level=INFO msg=“Using config file: /etc/vikunja/config.yml”
Mär 22 14:01:33 work vikunja[29110]: time=2026-03-22T14:01:33.413+01:00 level=ERROR msg=“service.publicurl is required when cors.enable is true”
Mär 22 14:01:33 work systemd[1]: vikunja.service: Main process exited, code=exited, status=1/FAILURE
I played around with different things, e.g. restart the service, ufw allow 3456, editing config.yml, but nothing helps. I doubt, that vikunja reads the config.yml, because, when I uncomment some lines with comments no error occurs.