How can I help my dog to not fear the dog door?

I installed a dog flap today, as the weather is freezing, and I want my dog to be able to come into the house when we are not home...but he is terrified of it...how to help?

Try putting his food or a treat on the other side of the door. Also, give him some time to become accustomed to it.

Draw a picture of a hot girl dog on the flap

try luring him with treats and a sweet voice-maybe hold the flap half way open with someone with a treat on the other side-he might not understand that it will move for him everytime.

Well they usually get scared because of the flap itself. To get the dog used to it, I would take the flap off and put food on the other side of it for them to be willing to go through. Or instead of food just go outside and call for them to come.

Gently, but firmly coax him through the door repeatedly, making a huge deal of rewarding him with a "treat" when he achieves the goal. It's more difficult for you than it is your dog, because of the fear and the crying...but you have to be the Alpha Dog...eventually he will get the picture! When I took my puppy for his first walk once, he cried and cried, as I took him for a "drag along" instead! But dogs are pretty smart...eventually they learn that they can peacefully walk along with you, or be dragged forever! After perhaps only five minutes of frustration, he walked along with me, as happy as could be!