oilslick wrote:
Sometimes the vent line can get filled with water sitting in a low spot, try taking the small vent hose off the back and blow it out, it used to do the same thing on our 2012 trailer so I shortened the vent hose and made it so there was no droop.
I also think this may be the problem.
If you have a large straw, or short piece of hose, hold it tightly against the vent hole by the water fill, and blow into it, forcing the water in vent line, back into the tank.
With the vent clear, you should be able to fill tank.
Jerry