Ok, we have everything eliminated...except the forward circuit. CA204-1 and CA204-2 on the distribution board are the switch outputs for forward and reverse. Reference battery negative and check CA204-1 for battery volts when requesting forward travel. If ok, put + meter lead on forward contactor coil, if ok...then contactor coil is bad

I removed and replaced all connectors, no improvement. Still no forward. Reverse and lift work fine. Is there something I can swap between forward and reverse circuits to see if problem moves?

On the distribution board, unplug...then plug in al the connectors. 80% of "gate"/"center handle" on display is caused by poor connector pins. Even a brand new board and connector can throw that fault

New forward contactor same problem, truck has new battery voltage not an issue

Check fwd switch, all other circuits have to be good to have reverse travel. A bad contact or will click but no travel and wont show code. If you lose signal anywhere before a fwd or reverse switch output when the controller senses throttle voltage with no direction input it shows gate. Can be gate switches at times but that would affect both directions.

"gate" can be
gate switches
gate switch relay
brake pedal switch
brake module
poor connection at distribution board
in your case i would suspect the forward switch has failed

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.

Sometimes it will give the error gate, but it's not the gate, check contractors and fwd and reverse switch in handle assembly, the contractor is similar to 50fc for faulting

I will check switches but I believe they are OK because the truck will lift without throwing a code, it also travels in reverse. trying to move forward is the only thing causing an error.

Gate is for the gates on platform if either is up it will not let you do anything. Remove platform cover and check switches. If they are ok check K3 relay on distribution panel of power unit. Gate signals run through it. Last is drive / tow switch on panel if someone released brakes with it and did not switch it back it will say gate also