the.com/barking up the wrong tree

means To pursue a mistaken line of thought or action, directing your effort or blame at something that isn't actually responsible.

from From American hunting with treeing dogs, especially coon hounds, who'd chase prey up a tree and then bark at its base to alert hunters. The phrase caught on because dogs sometimes got it wrong — barking furiously at an empty tree while the raccoon had long since leapt to another and escaped. First showing up in print in the US in the early-to-mid 1800s, it quickly left the woods for everyday speech, keeping all the comic indignity of a dog loudly, confidently, wrong.