I had the issue today and only found this search result. I spoke with Customer Service and they said the F2 code is for not having enough power. Make sure it’s not in a surge protector or extension cord, plug it directly into a wall outlet. If that doesn’t work, Hold the power button on the unit AND remote for 60 seconds and that does a hard reset.
An F4 code is similar, it’s basically a power loss while it was operating. Unplug, wait 1 minute and follow the same directions for the F2 code. He said if that doesn’t work it needs to be repaired/replaced.