Gore did not concede until dec 18 and after he had exhausted all legal remedies. In fact the Supreme Court ended it. In Gores’ concession he said although he strongly disagreed he accepted it.
I worked in the Florida Capitol during the 2000 recount... state Senate Appropriations. It was center of the universe for 36 days... me in the midst of it. Early on the night of the election the media inexplicably called Florida for Al Gore then later had to uncall it... then called it for George W. Bush announcing he was elected president. Al Gore conceded. We went to bed...
To wake up to learn overnight thousands of Gore votes showed up in Broward, Palm Beach and Miami-Dade counties. Putting Gore within a thousand votes of Bush... media uncalled again and Al Gore un- conceded.
Then recounts after recounts. As now in Pennsylvania, the then Democrat Florida supreme court ruled in favor of Gore... ignoring Florida election law. This forced the U.S. Supreme court to intervene and stop the madness. The Florida Legislature, controlled by the GOP was prepared to select the electors according the their authority per Article II, Section 1, U.S. Constitution.
Then Al Gore was checkmated and conceded again. Moral of the story: media companies don’t certify elections.