Maybe your dog sways too much on one side when he walks, so he hits the same side or edge of the door each time he goes out. Feel the door where the dog would hit and then tap the rough edges with a hammer until it is smooth. Most dogs love tape or anything they can play with or chew, so be careful about it getting any of that.You might even use a file to smooth the place if not too big. If it is almost new, you can probably take it back and get one size larger. Hope this helped some.