[Nithyanandham]

In ANSYS FLUENT, I am facing an adjacent cell zone error. The pipe outlet has two adjacent cell zones. If the Boundary condition for the pipe outlet is changed from Pressure outlet to Interior, the following message in the console is 'Wall 18 and wall 3 sewn together, wall 3 deleted.' Also, the mesh works. Boolean subtract has been used for the computational domain. The pipe and outer domain are with frozen material.
What do you think I should do to initiate the case with the pressure outlet boundary condition? Is there a mistake in the computational domain?. I've attached the screenshots here for you to look over. I'm expecting comments/suggestions from this valuable community to solve this issue. Thank you