I hope you all having good day.
To the point, I placed two mirrors, as shown below, but there is something wrong with the reflections, the reflection of front mirror and its image doesn't appear in the left hand mirror. I tried "Light Path" node but it didn't worked. any suggestions, please?
Thank you

I found the cause of my problem, It was the checkbox "Fast GI Approximation" under Light Paths. I was trying different presets, then suddenly It works, checked that checkbox again, and the mirror is black again.