When I have my camera (a Canon 6D Mark II) in AF mode, I can't take pictures (nothing happens when I click the shutter button) while using the viewfinder. I can take pictures using the screen though just fine. This happened after I sent my camera to a workshop for fixing another issue. I have used the lens that I am trying to do this with before and at that time it worked just fine.
The camera is not in video mode.