Do yourself a favour and clean your fans out!
I get up in the middle of the night expecting to see my 9 hour print completed, but instead I am faced with a Fan error and 45 minutes to go!.
Tried resume, but no good, checked fans and they both seemed OK, with the printer in error and the print incomplete my options were limited.
But the firmware (3.9.0) does allow you to do a few things, you can still go into settings and run the part cooling fan which I did, so there is nothing wrong here, but there is no menu item to run the hot end cooling fan, so the problem must be here.
I tried restart a few times and could hear the fan trying to start up, so I turned it with my finger a few times, then went into settings and turned fan check off and went back to restart and this time the nozzle heater kicked in and once it reached 50 deg, the fan started up again and the print completed, admittedly with me watching it like a hawk.
So next morning I checked the cabling by moving it and wiggling and everything short of taking it all apart and could find nothing wrong, so decided to clean the fan.
Using a Q tip or cotton bud moistened with IPA I cleaned around the inside of the fan and pulled out what I can only describe as a pea sized hair ball, also cleaned in between the blades with the other end of the q tip.
My feeling is that there was such a buildup of gossamer threads and dust that it was mechanically blocking the fan from turning freely and this was detected by the firmware and shut the print down and quite rightly as well.
So if you haven't done this before or not for a long time, do yourself a favour and spend a few minutes cleaning the fan to prevent problems.
Incidentally the part cooling fan gets a drop of oil on the bearing once every few months or when it starts to get particularly noisy and this has been working since new with this small amount of maintenance.