Apple Pencil battery couldn't be charged

I haven't used an apple pencil for two years and now I'm starting to use it Back.

but the pencil can't be charged. I've tried restarting the iPad pro and unpaired the pencil. Then I tried pairing Back but the pencil battery couldn't be charged. what should I do to fix it?

＊　タイトルを変更しました。　Apple Inc.