If everything else is cooking properly then something must be going wrong with the meat loaf.
I cook mine longer than the recipe says and cannot imagine why yours does not cook done..
This is the recipe I use.

Meat Loaf
2 pounds ground round
2 large eggs
1 cup bread crumbs (I use Italian)
1 bell pepper, finely chopped
1 pkg dry beefy onion soup mix
3/4 cup catsup
4 strips bacon
1 can tomato soup (do not dilute)
Combine ground round and the next 5 ingredients:
Mix well.
Form into a loaf and place in a 10 inch iron skillet: cover meat loaf with bacon strips.
Bake at 350 degrees for 1 hour.
Pour tomato soup over meat loaf and bake 30 more minutes.
Serves 6 to 8