The screw below the red Doris for vertical calibration of the rangefinder patch, not the actual focus mechanism and it needs a special tool. The adjustment of the infinity point is a 2mm Allen key at the inside top of the mount on the body side.
Look here for a detailed explanation.
If your lens rotates to infinity then you'll need have the rangefinder adjusted on the camera body. If infinity is out it's likely that close focus isn't accurate either as adjusting infinity also adjusts the overall focus throw of the rangefinder mechanism. If infinity is out, so will the rest, usually.