Canon EF 55-200mm won't micro adjust

[jegorrill]

This is an old lens I got used, and mount on my 6D Mark ii. It is focusing just behind my calibration target, but even with the most drastic micro adjustment settings for both Tight and Wide, it won't budge. The focus stays right where it was before the adjustment. I can't tell if it's a camera thing, or a the lens thing. Any thoughts would be appreciated.