Big Benjamin Armada Problems

Transfer port area? How did you determine that? Close the bolt and put a balloon on the end? 

If so, more than likely your valve is leaking.. if the gun is not that old, (several months) call Crosman and they should take the gun and offer a repair. Or check with the retailer to see if hey offer the repair. 

If you degassed the gun and then are trying to fill it back up, you can cock the gun and then try filling. When de-escalate, some guns striker springs force the valve open a tiny bit from tension.