I had the same problem on our 2017 Greyhawk.
Checked ground, checked voltage, checked all wire connections and unplugged the keypad thinking it may need to reset and even done a manual reset as instructed in the owners manual.
I finally tapped the reverser solenoid on the bottom a couple of times with a small hammer while the wife pressed the buttons on the keypad. It works as it should for a while at least. I'll be ordering a new one first chance I get.
By the way the selinoid is an Albright DC66-72P