Wattbike Atom resistance too high

Hi there,
I have had a look but can’t find an answer to this problem. I got a Wattbike Atom months ago and set it up with Zwift on Apple TV and it has always worked fine. I’ve had a break for a month and got back on it yesterday and the resistance is insanely high in the training programmes. I can barely turn the pedals, then zwift swtiches ERG off and I go into 1st gear to get my pedals moving again, then ERG comes back on and within seconds resistance is too high to pedal again. Any advice? Sorry if I’m missing something super obvious.