Facebook blocked an election candidate from posting adverts after it wrongly recorded his County Down address as being in the Republic of Ireland.
Northern Ireland councillor Cadogan Enright, who lives in Downpatrick, is seeking re-election as a member of Newry, Mourne and Down Council.
He has not been able to advertise on Facebook for more than nine weeks.
He believes the error is due to new rules aimed at preventing foreign interference in election campaigns.
Facebook said it was sorry for the difficulties Mr Enright had faced due to the new rules.
In 2017, Facebook founder Mark Zuckerberg pledged to make political advertising more transparent on his network, after the firm was caught up in controversy over alleged Russian interference in the 2016 US presidential election.
Mr Enright is among Facebook customers who now have to confirm their identity and address before they can run political adverts.
He told BBC News NI that since the problem emerged more than two months ago, he has provided Facebook with 29 separate forms of identification in order to prove that his Downpatrick address is in the UK.
He also asked the council’s chief executive to write a letter for Facebook, confirming that the entire Newry, Mourne and Down Council area is located within Northern Ireland.
However, nine weeks on from his first complaint, the issue still had not been resolved by the social media network.
Last week, he received a message from Facebook’s client support team apologising for the “inconvenience” he has experienced.
“It is my understanding that our system has located your post code address BT30 6DN (UK) to the Republic of Ireland and you are able to complete the ad authorization process,” the message stated.
“Please be informed that I am working on this case with our expert team. As soon as I have any information, I will let you know.”
The councillor said he received a call from a Facebook manager on Tuesday morning, shortly after his story was published in the Irish News, but the advertising ban still had not been lifted.
A Facebook spokespeson said: “Last year, we introduced new tools and policies in the United Kingdom to help prevent abuse and election interference.
“Our enforcement of this policy will never be perfect, and we apologise for the delay in this case during the authorizations process”.
Mr Enright is one of several candidates seeking election to Newry, Mourne and Down Council in the local government poll on 2 May.