Unable to add box simplified collision

Hi Guys, how are you doing! I am facing an issue regarding mesh collider. Details below.

So i have imported a full interior scene as a single mesh in UE4 , with separate mesh selected. What i needed was a hit detection on each wall , so that i can assign different tasks to each face like , changing color , material etc. So far i have assigned box collider to each individual wall mesh , and for most of them, it is working fine.

Issue rises with some meshes, about 5-7 meshes , the collision is not working and i am getting this error.
LogPhysics:Warning: AddBoxesToRigidActor: [/Game/Meshes/RedSeer/Walls/Wall_Walls_351.Wall_Walls_351] BoxElems[0] invalid or has invalid transform

So why this issue with some mesh only?, i have exported from Maya as a single fbx file. with history deleted and reset/freeze transforms.

Kindly help me out with pinpointing the issue or where i am doing it wrong.
I am posting an image for you to follow easily. looking forward to your replies.
Thanks