Leak in drain pipe connection under slide-out

[Patrick Cook]

2013 Bay Star has a leak under the slide-out pantry where the black fitting connects with a brass connection. When the slide opens, I have water on the floor. After investigation, I see the brass fitting(connection) rotates when the slide moves in or out (not sure if its meant to do that?). I attached a photo showing the brass fitting with the connection to the PVC black pipe. The leak is where the PVC pipe threads mate up with the brass fitting. Any help with this issue is greatly appreciated.

["007"]

As long as the black fitting is not cracked it should not leak. The brass fitting into the black pipe should have white pipe tape on it so no leak around threads. The brass fitting looks like 1/3 of it can be turned to tighten into black pipe.
This link will help you also.

Newmar search engine ===== results