I tried to utilize MirrorReflection shader, but when I used it in my scene, lightmaps disappeared as a strange error and I couldn't select other objects around the object which has this shader.
So, I tried to use Reflection Probe and an object with full metallic and smoothness values. I make an AR application on android with Vuforia plug-in. After the build, the problem which you can see in the photos below occurs. I tried a lot of things but couldn't figure out the problem.
I will try any idea coming from you. Also, if you encountered MirrorReflection problem, please tell me the solution.
Note: I just disabled left and back walls after baking everything in order to see the mirror in AR app.