An E0 code usually means the machine can't generate pressure, or it isn't detecting a keg.
What to try
1. Open and close the door.
This resets the machine and often clears the code on its own.
2. If you've put a nearly empty keg back in
A keg that's almost empty can lose pressure while it's been sitting in the fridge. Open and close the door a few times and the machine will build the pressure back up.
3. Check the connections.
A poor keg connection is the most likely cause. Take the tap unit off, refit it, and check the beer line and keg connections as you go. You should hear two clicks when the tap unit is properly seated on the keg.
4. Try another keg, if you have one, to rule out a keg fault.
Still showing E0?
Get in touch and we'll help. Let us know what you've already tried and whether the keg is new or nearly empty.