I'm not sure why, but for some reason, my camera isn't working.
I don't know why, but my camera won't turn itself on.
ご質問ありがとうございます。
① "I'm not sure why, but for some reason, my camera isn't working."=「なぜか分かりませんが、何らかの理由で、私のカメラは起動していません。」
② "I don't know why, but my camera won't turn itself on."=「なぜか分かりませんが、私のカメラがオンになりません。」
ご参考に!