This issue usually happens if your Pinterest Tag events aren't being fired within a seven day period.
If the events are firing correctly, I would recommend reviewing your Pinterest Tag installation. You can check out our Help Center article to learn more about this.
Also, please bear in mind that it can take up to seven days after an event is fired for the Pinterest Tag to be considered healthy, so you'll need to wait for it to be updated. I would recommend checking Ads > Conversions and making sure that Pinterest is receiving the Tag fire information.
I hope you were able to solve it. Let us know if you have any questions!