Facebook said late Thursday that a mix of "technical problems" and confusion among advertisers around its new political ad ban rules caused issues affecting ad campaigns of both parties.Why it matters: A report out Thursday morning suggested the ad tools were causing campaign ads, even those that adhered to Facebook's new rules, to be paused. Very quickly, political campaigners began asserting the tech giant was enforcing policies in a way that was biased against their campaigns."It is currently unclear to us whether or not Facebook is giving Donald Trump an unfair electoral advantage in this particular instance, but it is abundantly clear that Facebook was wholly unprepared to handle this election despite having four years to prepare," said Biden for President digital director Rob Flaherty in a statement provided to Axios.Details: In a post addressing the issue, Facebook blamed the blockage on a technical glitch and said it's investigating the issue. The tech giant asserted that "No ad was paused or rejected by a person, or because of any partisan consideration."Catch up quick: Facebook implemented its new political ad ban rule — which restricts political or issues ads from its platform for the week leading up to the election — on Tuesday at midnight. Advertisers had been racing to get their ads approved and running before the ban went into effect so they could continue to show the messages to voters for the week leading up to the election while also following Facebook's rules.The big picture: The tech giant has been slammed by critics on both sides of the aisle for a lack of transparency in the way it enforces its policies, leading some to think it's biased against one political party over another. On an earnings call with investors, CEO Mark Zuckerberg said the company was focused on providing more transparency around the way its platform is used and the way it makes policy decisions.By the numbers: Facebook COO Sheryl Sandberg assured investors that political ads are only a tiny part of the company's bottom line on the same call. She noted that political and government ad revenue in the U.S. and globally was a low single-digit percentage of the company's total ad revenue in Q3. “It's not a top 10 vertical in the U.S. and globally."Be smart: Facebook often tries to downplay the role of political ads in its business, to make the case that its decision to continue to sell those ads is about its First Amendment values, not revenue. The company keeps finding itself in complicated battles with both parties over its political ad policies.Some of its competitors, like Twitter, have banned political ads altogether.Go deeper: Political ads become 2020 flashpoint