Are you trying to pin from your live listing?
yes of course
Do not pin to Pinterest from Etsy, it's counter-productive for your shop. Create a Pinterest account, and make your own pins with a direct link to your shop.
I had that problem if I went through the normal store page. But then I went to listings, then the share button then it worked. It wont let me from my store to share. Facebook the same way.
@VintageByTiffinie: You can always pin directly and you might want to read the post by @DKVintageandBeyond https://community.etsy.com/t5/Technical-Issues/Social-Media-Posting-not-working/m-p/142790482#M78716...