Heat conjugate problem

pepa

I have a problem with my model. I'm modeling a tube with metalic surrounding body. There is flowing hot gas in the tube. I made a geometry in Gambit and I specified the the fluid zones and BC. In imported the mesh into the Fluent 6.1 and the Fluent made the wall(coupled) and wall.shadow(coupled) on the interface between solid and fluid zone. Than I specified the BC, models - laminar flow, steady state, energy equation,velocity inlet, pressure outlet etc. The temperature of the hot gas is 573 K. When I run the simulation, the temperature of the metalic body is going to 260 K and it cools the gas hot stream. Please can you help me where is the bug?! I tried to make the simulation with 0 heat transfer from gas zone to solid zone and the solid zone reached the temperature 1K. It is not normal. Please, do you have any idea how to solve it?!