Hi @saravanan17

It looks like the following surfaces are adjacent and are matched B181FE (construction: INTERIOR WALL) and 79CCC7 (Construction: EXTERIOR WALL).

Since surface 79CCCC7 is adjacent to another wall, I presume an incorrect construction has been applied to it. You can change the construction of this wall to INTERIOR WALL and try running the model again.

In general - for adjacent surfaces, the constructions layers need to be symmetric at the line of separation.