Hi! I have a tapo rv30 robot vacuum cleaner! It has been working very well for a while, but it has been writing error 4 error codes for 3 hours! I did all the steps written in the app, but it still says the same error code! When I start a turbo/max cleaning, I don't hear the engine/fan starting! Can you help me or do I have to find a service or send it back for warranty?