Check out the video below to see what this means and what to do about it.
If you prefer not to watch videos, we suggest your go to the Facebook Ad Tracking Screen
You will then select Historical Data and pick Yesterday's Date
In the results of this search, you are likely to find the Ad(s) which had an error. This means that YESTERDAY, that ad or ads had an error. If you've fixed the ad or turned off the ad since then, you are likely fine.
If not, once you see which ad(s) is causing the problem, you can switch back to the Live Data and find the Campaign this ad is in. Then you can update the Ad(s) as needed for proper tracking.