black water tank fitting leak

 I have a 2017 RPod 179, and I have a leak at the fitting going into the black water tank. I think this is the tank flush line. It is on the same side as the entry door and flush fitting. It appears to be a rubber flange with 3 screws. I tightened the screws but that didn't help. I didn't want to open this up until I had a solution or replacement flange. Has anyone dealt with this before? Does this conect to anything inside the tank that I need to be aware of before removing it, or does it just fill the tank? Changing it seems easy enough if it is just a flange for the hose connection. Are there schematics of any of these plumbing systems anywhere?

No schematics here, but it definitely looks like the sealant around the perimeter of the flange has failed. It looks like the fix is to drain the tank, remove the old one, clean the area thoroughly, and reinstall with new clear silicone sealant. Let it cure completely before using. See this link for some possibly useful information.