sudo systemctl reboot works fine for me. You should check your logs to see what hung your reboot, or attach your journal logs from a boot where you reproduced the problem.
** Changed in: systemd (Ubuntu) Status: New => Incomplete -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1928564 Title: systemctl reboot hangs the machine under hirsute 21.04 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1928564/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs