I did read one post here that told of a blockage in the grey water tank. It turned out when the hole was drilled for the drain the wood piece fell into the tank and caused the blockage when it became wedged in the drain pipe.
If you can't get to the dealer right away you may want to disconnect the sewer hose and see if you can get a snake up into the grey drain line.
Joe, Joyce , 4 Kids and 3 Dogs.
2004 V-10 Excursion with Hellwig sway bar, Roadmaster Active Suspension, Bilstein shocks and steering stabilizer, Super Duty Tow Mirrors,
3.73 Gears, Reese dual cam, Prodigy brake controller.
2010 Jayco Jay Flight G-2 32 BHDS