The operator of the Premier League's goalline technology system has apologised after an error denied Sheffield United a goal in their 0-0 draw at Aston Villa.
Villa goalkeeper Orjan Nyland carried Oliver Norwood's 42nd-minute free-kick over the line.
But referee Michael Oliver did not receive a signal to indicate a goal.
"I think the goalkeeper was in the Holte End when he caught it," said Blades boss Chris Wilder.
Hawk-Eye said it "unreservedly apologises", and acknowledged that the ball had gone over the line.
The company added it was the first time such an error had occurred in more than 9,000 matches using the system.
It explained that all seven of its cameras monitoring the goal were obscured by either the goalkeeper, a defender or the goalpost.
Wilder, who was seen to approach Oliver at the interval, added: "Seven cameras haven't picked it up - the most technical league in the world - everything we see at every angle and it hasn't seen a goal.
"We went to Tottenham last year, John Lundstram's big toe was offside and I was hanging around in the pouring rain for 10 minutes waiting for a decision. I don't understand why I can't wait 10 minutes in Birmingham.
"The statement has come out and it is unprecedented, unbelievable."
The body responsible for Premier League referees - the Professional Game Match Officials Limited (PGMOL) - said that video assistant referee had not intervened due to the "unique" situation of the on-field match officials not receiving a signal.
Hawk-Eye added that the system had been tested before the match, and was confirmed to be working by referee Oliver and his fellow officials.
The company said: "Hawk-Eye unreservedly apologises to the Premier League, Sheffield United and everyone affected by this incident."
In what was the first Premier League match since 9 March - the season having been halted by the coronavirus pandemic - the result leaves the Blades in sixth in the Premier League, while Aston Villa remain 19th.
Before the match both sets of players took a knee in support of the Black Lives Matter movement.
How social media reacted
Sheffield United's Twitter account posted two messages in response to the goalline technology failure: "Really?" and "it wasn't working".
West Ham's Declan Rice wrote: "Wait... I thought this is what VAR was brought in for? Blatantly over the line, while Norwich goalkeeper Tim Krul simply posted the word "shambles".
And the controversy also brought a wider response on social media.