I hooked up my sink today.
When I tested it for leaks, I found I had a leak between the sink and the rubber drain washer.
Not below the rubber washer, above it.
I took the drain apart and discovered there is a small chip on the edge of the drain, where the rubber washer should seal.
I’m not sure how to get this to work. This is an under mount sink, so changing the sink would be a major deal.
I have attached some pictures. Any suggestions would be much appreciated!