Try this in Ads Manager
Go to Ads Manager.
At the Ad level, click Search and Filter.
Filter by Delivery → Deleted.
Find the deleted ad.
If it appears:
Duplicate it into the same ad set or a new one. This recreates the ad, though performance stats start fresh.
Or click Preview → Share → Facebook post with comments and open the post. Copy the post ID from the URL.
Create a new ad and choose Use Existing Post, then paste that post ID. This can preserve likes, comments, and shares on the original post.