Protection is to prevent "me too" or "thanks" answers by new users.
What is the correct equivalent of "me too" that I should use instead of commenting "me too"?
If you have the same problem, upvote the question. If you agree an answer is correct, upvote the answer. There is no need for a comment saying that you've done so, and commenting without voting is useless since it doesn't help people identify good questions and answers.
As Kate already said, it is best just to upvote the post.
Commenting in this case should only be done when you have useful information that doesn't directly belong into the question. If you have for example some extra information on a particular bug, like a browser version, etc. you can comment that.
If you think it is appropriate, edit the question into shape if that hasn't been done yet. That will increase the possibilities for both of you to get an answer. You might even raise a bounty to bring some extra attention to it.