The gate should be suitable for the 777, as it is a heavy gate both in real world frequently used by triple sevens as well as in your excellent JFK scenery (Terminal 4 gate A5, in the product it is Gate 405)
Sure, it might be suitable in real world, but what I was saying is that it's not suitable for a 777 in this scenery!
GSX considers it suitable without any modifications to the parking position.
GSX only reads the parking radius, it doesn't know anything about what the jetway model on a parking can do or will look like.
The jetway is indeed properly connected to the fuselage and door, but its undercarriage is high up in the air.
This means the jetways is working, it's just the model is not designed for a 777. Not possible to fix it without updating the scenery, adding new jetway models that could reach higher on some parkings.
We'll note it when we'll revisit JFK, which will surely use enhanced SODE jetways.