Another trick when he comes out of crate if you can not get him to potty outside put a harness with a leash and tie him to your belt loop so he can not hide from you to go potty inside all dogs have signs they are gonna potty usually turning circles an d sniffing area to use learn his sign. Be positive even if he does go inside take him out and show him where to go take him and poop outside if he goes inside and put it in same area every time so he knows were to go at if you scream at him hit him he will think that it us bad to potty anywhere and hide from you when he has to go and more than likely he can't hide outside like he can inside! Age have a bell on our door and my dogs jingle it when they need to go out! But u can not express enough do not be mean to him be positive even if he has an accident he is a baby at 4 months you have to teach him he doesn't know what he is doing all he knows is that when he pottys you get mad so he is scared to do it. Feel free to call or text me with more questions ( 615)946-8662 I have 4 mastiffs over 100 lbs each lots of experience.