Leave it on since the fan is actively trying to cool it - but barring it actually being a heat issue some folks have found that one of the cord connections gets loose and this error pops for some reason.
If it hasn’t come back to finish after 1 hour and 30 minutes you may need to cancel and reboot - but figure out what was left to do in the 51 seconds, and you can create a file with just those movements. As long as you don’t move your material at all you should be able to line it up with the prior art in your GFUI (ignore what it looks like on the material. Match exactly to the art in your GFUI) set your prior art to ignore and set the 51 second job to go and finish your piece.