My F2 error was caused by a failed fan, which in turn caused the cooling elements to overheat and triggered some sort of thermal cutoff. This is likely the issue for you too if these criteria are met: (1) the cube is on cooling mode, the issue does not occur in heating mode (2) you can't see your fan spinning through the fan guard (3) after some time to cool down (around 5 minutes), you are able to turn the cube on again and the error has cleared