Hammer Editor question. How to fix this?

[DrewKach]

Guys, i need to fix this weird (shadows?) grey boxes on my walls.
Are there any ways to fix that? I used full compile.

https://steamcommunity.com/sharedfiles/filedetails/?id=1586655555

https://steamcommunity.com/sharedfiles/filedetails/?id=1586655467

https://steamcommunity.com/sharedfiles/filedetails/?id=1586655521

[canI]

Hammer Smoothing Groups Dialog

[DrewKach]

Thank you very much. I tried it once but i thought its not what could help me.
Now i tried it again and it seems to be very useful.