Open passage through wall

Hello dear Unreal Enginge Community. I would have a problem with the program, where I couldn’t find a solution yet and hoped to find it here.
If I build a wall and put an open passageway in it, I can’t walk through it with my character if I want to test it. It simply remains standing in front of an Alpha wall. Maybe someone can help me and tell me how to handle and solve something like that. It should be a big passage in the wall and not just a smaller door. Like a big company building.
I thank you very much for any kind of help and look forward to your answers.

Yours sincerely: S1G CO CEO