AC error code E1

2011 North Trail. We see the error code E1 flashing on the the thermostat. The little book says it can't communicate with the board and the unit will shut down. However, it runs like a champ and cools very well, just has the annoying error code flashing. My wife got it to go away once but doesn't remember what she did.
Anyone had this issue and have a solution?

I have no clue what is wrong. Put a piece of electrical tape over it. Out of sight-out of mind.

I am not at home but I believe E1 is error for zone. Make sure your in zone 1.