leaking pipes

We recently noticed small water leaking out of our secondary clean-out pipe. We contacted a plumber to have it looked at he noted the clean-out valve was positioned downhill so a lot of the water would collect here. The plumber ran a snake through the line to determine if there was any kind of...

Not sure where to put this but nead assistance with bathroom sink underneath. I took the pipes apart and cleaned it out as it needed it. Water was not going down. Now I thought I had put the pipes back together correctly, elbow and all. Unfortunately, it is now leaking underneath from the plug...