Facebook can make ad campaigns sit in limbo for days while it goes through a stringent review process, leaving marketers to wonder if they will ever publish.

But the company also reviews and investigates the behavior of the advertiser — looking at the number of previous ad rejections and the severity of the type of violation, including attempts to get around Facebook’s ad-review process.

Advertisers that violate the policies may have actions taken against them, including losing the ability to run ads on Facebook.

Facebook estimates it had about 1.88 billion daily active users in the first quarter of 2021, reported eMarketer, with each viewing ads when they log in.

Last week the company published an overview of its ad-review process, but it doesn’t fully explain why it may take a long time to reject or approve an ad.

All ads are first reviewed by Facebook’s review system, an automated technology that typically reviews and applies their advertising policy on millions of ads running daily on the platform.

The ad review process typically takes 24 hours or less. But sometimes an ad can be reviewed twice, writes Jeff King, vice president of business integrity at Facebook, in a post.

The first review is usually completely automated, whereas a re-review is done manually by professionals. However, Facebook says the company is working toward making this process completely automated.

Advertiser accountability also comes into play. There are reporting, authenticity and transparency features to encourage advertiser accountability. People can report ads that they believe violate Facebook policies by clicking the three dots in the upper right-hand corner of the ad. They signal the ad-review systems, and may prompt a re-review of the ad.

There is also a publicly available searchable Ad Library that enables people to search for all active ads across Facebook.

Ads about social issues, elections or politics have an increased level of authenticity and transparency, King writes.

King also admits enforcement isn’t perfect, because both machines and people make mistakes.