"coalmanham"....You're experiencing a common problem with the Dutch Star door and one that many have complained about. Here is the issue. The latching mechanism has what is called a "star" adjustment. It's only adjustable by removing the wood trim around the inside of the coach door. This is a pain. They could have simply made the latch more accessible from the door frame by making a bigger cover plate.
Your door has two closing positions. If you look when you close it, it will latch in the first position when the door is closed normally. It seals in this position, but you'll see the door is slightly open on the latch side. It's actually designed to do this. While camping and even locking the door, you only close it to this position.
When you're ready to drive the coach, you need to close it hard to the second position to keep it from leaking air. When we get ready to drive, I place one had on the door frame where the latch is located and pull the door closed hard, to seal it in the second lock position.
When the coach is parked for long periods of times, like in storage, you should close the door to the second position (driving position). This helps set the rubber molding so it's not as hard to close.
Don & Mary
2014 Newmar Dutch Star - All Electric - 450 ISL
2016 GMC Canyon 4WD Crew Cab