Meaning:

To misunderstand a situation and complain to a wrong person or blame a wrong thing.

If someone is barking up the wrong tree, he/she has an incorrect idea about a situation, and his/her course of action is wrong.

Example:

Don't blame me. I have nothing to do with it. You are barking up the wrong tree.

The committee spent more than 5 month to try to solve the problem. They were just barking up the wrong tree.

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