When you create a Facebook or Instagram Ad, these are screened to confirm policies are met. Facebook has a set of automated Filters to conduct the screening process. The Filters search for banned words in both text and audio, screens the background music, and even can test the image with something called the Skin Pixel, which is designed to check posts for nudity.
If these Filters pick up a banned word or breach of policy, the Ad will be automatically refused. When this happens, a request can be placed for Manual Review where the Ad is looked at by an actual person. Facebook will still have the discretion to approve and disapprove any Ad it wants.
The system is not always logical and Facebook has been publicly criticised on its rules for what is acceptable and what’s not, so the rules can often be a little bit murky.
So let’s avoid confusion here. You can post almost anything onto your Facebook Business Page Timeline, but if you want to promote that Post or set up an Ad, these policies are likely to prevent your Ad from running.