Can you determine which end has the threads out - the N adapter or the port?
Then using a padded jaw pliers and the hex wrench, turn the nut that doesn’t have the threads exposed. I would guess the port has the exposed threads and the N adapter is threaded on. In this case turn the hex nut CCW.
If this is not the case then turn the port collar collar to release the connection.
Someone put it on too tight or really tightened an N cable onto the adapter, spinning both adapter and cable, over tightening the adapter to the port. Do use the padded jaw pliers with the hex wrench so that you don’t twist the port connector.
Don Bitters
