Unwanted line revealed during Cycles Render While rendering in Cycles, an unwanted line revealed on the green wall. It didn't show up in Eevee. In wireframe mode, it doesn't seem to be any problems either.

How should I resolve this?
Appreciate all the help. Thank you.
It's likely due to the fact that you used a boolean to make the wall. Booleans are notorious for ugly topology - for example, blender works best with quads (faces with four vertices only) and any more vertices (n-gons), or any less (tris), will often cause shading errors. That being said, take a look any of the (single) faces that makes up the door in your image - how many vertices can you count on those faces?
The solution in many cases, is to use a simpler object for your Boolean, which makes it easier to connect loose vertices manually. If you need things to be round, you can &quot;round things out&quot; using a Subdivision Surface Modifier and/or Smooth Shading if necessary.
In the image below, the &quot;wall&quot; on the left is made using a cylinder with 8 faces as the cutout object, and the wall on the right uses the default 32 face cylinder as the cutter.

Since the 8 sided cylinder leaves a much more workable number of new (extra) vertices, it is a trivial matter to connect them to the rest of the mesh in a manner that leaves only quads. Because of this, I was able to apply a Subdivision Surface modifier and Smooth Shading without incident.
While the wall on the right is technically capable of being connected in such a way that it leaves only quads, the sheer number make it a time consuming effort, and will leave your mesh much more subdivided than it originally was. Because of this, I left it in it's fresh post-boolean state (without making quads) to demonstrate why it's necessary. The topology is so bad that I cannot use a Subdivision Surface Modifier without serious mesh-breaking errors, and so I did not use one. I did Shade Smooth, but you can see the shading errors that are a result of the n-gon faces.
The TLDR is that Booleans leave &quot;poor&quot; topology that often must be connected to the rest of the mesh manually to convert it back to a quad-only state and avoid shading errors. To make the manual connection process easier, use a &quot;cutter&quot; object with as few faces as possible, and do the rest with other modifiers if necessary.