Boot does not sit flush to tub, causing drain to not tighten evenly.

Took the drain out to remove hair from line. Then, I reinstalled and it leaked to the bottom floor. Upon closer examination, the PVC does not sit flush to the tub, which means the rubber gasket is not sealing evenly; it also means that when I tighten down the drain, it doesn't seat evenly or all the way flat. I used plenty of putty after various attempts to see if it will seal flat, which it just won't. However, I'm fairly certain I've secured all the open cavity with putty.

There's also no trap door to the tub, which could have allowed me to try to play around with the pipe as I'm tightening down.

Is there a way I can make sure this will not leak again? Any ideas?

Thank you!