How can I convince the doves?

I built a house for the doves. There is a couple that lives in the tree in front of my apartment. Winter is coming. And this year i wanted to build a shelter for them. They were never able to build a nest; they gathered twigs from the ground, but never got it together.

The thing is, the entrance inside the "house" is through the porch. And I sense they are scared to go in this way.
I put food, and they do eat it, but never dare to go inside.

Maybe if I close that entrance, and make on from the outside? With a tiny ledge for them to land on, and then go inside?

Looking at the house, it can feel like a trap. Something that they will never accept.

This is how it looks like https://www.instagram.com/p/DQtmaheCO5d/

what