The United Arab Emirates orchestrated the hacking of Qatari government news and social media sites in order to post incendiary false quotes attributed to Qatar's emir, Sheikh Tamim Bin Hamad al-Thani, in late May that sparked the ongoing upheaval between Qatar and its neighbors, according to US intelligence officials. The May 24 hack was very much the instigator, however, as well nations like the UAE were angry with Qatar (as evidenced by the May 23 plot meeting), they weren't overtly blockading them until the hack and the false quotes attributed to Qatar's Emir came out.
The United Arab Emirates has denied its involvement in the alleged hacking of Qatar's state news agency. I have no idea if this is true - but the story is sourced to "U.S. intelligence officials" so presumably the reporters got it from someone inside the IC (and given that it looks like SIGINT, probably from the NSA).
Five countries - the UAE, Bahrain, Saudi Arabia, Egypt, and Yemen - cut ties with Qatar over claims it had destabilished the Gulf by supporting extremist groups.
The Post reported that US intelligence officials learned last week of newly analyzed information that showed that top UAE government officials discussed the planned hacks on May 23, the day before they occurred.
Among the false social media posts published during the hack were some made in the name of the emir of Qatar, in which he appeared to make disparaging remarks about Donald Trump, praised Gaza's Hamas leaders and expressed support for Iran as an "Islamic power". For the record, the UAE ambassador and foreign minister have denied the report, but they would have to. The emails highlight a years-long campaign on the part of the UAE to court Washington support for its ongoing dispute with Qatar. The US Office of the Director of National Intelligence, the Central Intelligence Agency (CIA), and the Federal Bureau of Investigation (FBI) declined to comment, according to the newspaper. Over the last two decades, bilateral pressure on Qatar has not yielded results.