Chamberlain myQ won't connect to ADC

Forgive if this is a repeat.

I bought a new Chamberlain myQ B4613T and can’t figure out how to pair it to my ADC system. I get an error when I enter the serial number saying “The request to register your LiftMaster MyQ Gateway on your account failed due to an invalid serial number. Please try again. Serial Number -”

It looks like this question was also posed in a private message. Looking at that message it looks like the correct MyQ Serial Number off of the unit was not used.

The correct number will be a hexidecimal value labeled MyQ Serial Number and will have the form: XXXX XXX XXX