need advice on 400 f5.6

I can not get a shot in focus with this lens. I tried to micro adjust but no help. I tried using a tripod, using live view 10x, remote shutter and manual focus. My shots are still oof. Could this be a bad lens or still pilot error? What next? I've seen what this lens can do and getting very frustrated

Post examples.

With Exif.

This is a recent handheld shot. I had to push the iso to get my shutter speed up. Another missed oppurtunity

Target is so small I doubt AF can find it.

AF found the target just fine. I get the same oof shot when I focus to the telephone pole across the street from me.

Form the example posted, it looks like the fence to the left of the bird might be in focus.

I'd say it's time for some specific, controlled focus testing.

Sounds odd that you couldn't attain proper focus manually.

Are you able to see ~any~ area in focus?

And what, specifically, were you doing when adjusting MF?

You may need to adjust your view finder.

I had the same problem with mine and sent it in to Canon who recentred it. After getting it back and slight M.A. it's now spot on.
I could get a sharp shot of the above target with mine, AF would lock onto that, I regularly photograph tiny birds at greater distances with no problem.

Is there a UV filter on the lens. If so remove it. Few UV filters are optically flat enough to not cause problems at 400mm. Price isn't much of an indicator either.