Update From Amelio
After my six week vacation with the tolet problem I brought the Rockwood trailer to the dealer. It has been there for three weeks. they fianlly dropped the tank and found that the tank is too shallow where the waste pipe enters the tank.
(2-1/2 to 3 inch clearance at the entry in the tank). That is where the blockage occurs. A new redesigned tank is being shipped. Hopefully, it will have a deeper tank design.
I will keep all of us informed.
Thanks for all the suggestions