How to fix leaking bathroom sink drain where PVC meets ABS connection?

My bathroom sink drain began leaking recently. The PVC connection that meets the ABS connection is the culprit. See picture with red arrow below.

After taking everything apart and cleaning the parts, I discovered the ABS threads look to be dented (see picture). I suspect the leak occurs because the tapered gasket cannot form a water tight seal where it meets this dent.

How do I fix this?
Can a material of some kind be added to fix the dent, but still allow the threads to work? Do I have to replace the ABS thread connection entirely? I'm not sure how to do this exactly since I believe ABS connections are cemented. Guidance is appreciated if this is my only option. Other?
It looks like there may be a glue type residue on the ABS threads. I wonder if there was once glue of some kind that broke down over time and caused the leak now. I can't imagine why this connection would have sealed without some kind of other stop gap measure in place to account for the dent.


#Drain #Leak #Bathroom