Why my Pinterest feed isn't displayed in Social Feed
If you can't see your Pinterest feed in the Social Feed widget right away, please do not worry.
The issue lies in the fact that Pinterest doesn't provide publication dates for its posts. Consequently, when you choose to sort your posts by publication date, the Pinterest feed may appear after content from other connected sources.
To make sure that your Pinterest feed actually works, you can set the sorting to Random in the Sorting section of the Sources tab:
Scroll down a little, and after a few posts, you'll see your Pinterest feed among other sources in your Social Feed widget.