Leaky oil pan plug

Cant seem to stop my drain plug from dripping oil.

Its a brand new Summit 360 pan. Drain plug came with a white nylon gasket, it leaked, so I went to the store and got a copper one, it leaks. Don't dare tighten the thing any tighter, don't want to strip out my new pan.

Does anyone make a drain plug gasket that's a softer material, or with an o-ring or something that will seal better?