If I remember right the F/R contactors will show no error just not move one direction because either one contactor is not closed completely or the other is not open/actually in the reverse closed position completely.
Probable cause is the forward switch sticking if the reverse switch was not working you would get a center handle message.
To Crown a Gate is just a term for a open circuit. If it was a gate switch then it could not have everything working but the reverse travel.