How do I find out what is causing this?
journalctl -b -1 would seem to be a good starting point, given the lack of detail on screen.
The message was Failed to execute shutdown binary. Not sure if you can edit the title. Read man shutdown . Did this occur when attempting to shutdown or after some sort of “crash”? I’ve never seen that message running Fedora Workstation. Please post the output from running inxi -ezxx in a terminal (as web-discoverable pre-formatted text) so others with similar hardware and software can comment.
If this was due to a “crash”, you may be able to find issues leading up to the crash in the journal.
I’d be curious if systemd is intact, have you tried this;
systemctl poweroff -i
some how high temperatures hat dislodged the nvme. After removing and reseating the system booted normally.