I installed a new sink drain and the pipe does not align with the existing pipe. The existing pipe is about 1/4" off center with the drain and the angle does not allow a tight fit, even though I can screw it in.

Is there some type of putty or something else that can seal the connection so I don't have a leak. Right now, whenever I try to tighten it up, I get to a certain point, and if I go further, it loosens up.

Are you saying that the trap will not swing left or right to line up with the sink tail pipe or are you saying that when swung all the way left or right it still won't line up. What type of trap do you have, a glue up, or does it have an arm going toward the wall stub out by which you can move the trap forward or backward.

Sounds like you have the nut cross threaded and it is poping loose when you really tighten it. Stop, you are only ruining the threads. You also could have a broken nut.

Can you post a picture.

Thanks for your reply. After taking a break and starting fresh this morning, I switched the plastic nut with a metal one and also removed the 3 bolts from the bottom of the new drain that provide the counter pressure to keep everything snug. With those removed, it was then much easier to tighten the nut correctly. I reinserted those screws and after tightenng everything, I'm happy to report that there are no leaks. Thanks for your quick reply and help.