Nottingham Forest have been hit with a £750,000 ($979,526) fine for a social media post last season aimed at video assistant referee Stuart Attwell, the English Football Association (FA) confirmed on Friday.
Forest have described the sanction as "wholly disproportionate" and said they are going to appeal the decision.
The post in question followed their 2-0 defeat to Everton on April 21, a time when both teams were embroiled in a relegation scrap. Luton were also involved in attempting to battle the drop, and Forest questioned Attwell's impartiality on the social media post.
"Three extremely poor decisions -- three penalties not given -- which we simply cannot accept," Forest said on their official X account. "We warned the PGMOL that the VAR is a Luton fan before the game but they didn't change him. Our patience has been tested multiple times. NFFC will now consider its options."
A statement from the FA said Forest had also been warned "for misconduct in relation to comments posted on social media" alongside the fine.
The statement added: "The club denied that the comments posted on social media imply bias and/or question the integrity of the match officials and/or the video assistant referee and/or bring the game into disrepute.
"An independent regulatory commission found the charge to be proven following a hearing and imposed the club's sanctions."
The charge relates to a breach of FA Rule E3.1, with Forest's social media post guilty of constituting "improper conduct in that they imply bias and/or question the integrity of the Match Official[s] and/or the Video Assistant Referee and/or bring the game into disrepute."
Forest released a statement after their punishment had been made public.
"Nottingham Forest Football Club is extremely disappointed with the decision of the Regulatory Commission to impose a £750,000 fine in relation to comments posted on social media following our Premier League fixture against Everton on Sunday 21 April," it said.
"We are particularly concerned that The FA, in its submissions, sought a sanction "in excess of £1,000,000". We believe that this request, along with the subsequent fine, is wholly disproportionate and the Club will be appealing the decision."
Forest were angered by decisions made in the match, with all three penalty claims focusing on Everton's Ashley Young.
They were bothered by one tackle Young made on United States international Giovanni Reyna, an alleged handball off a Callum Hudson-Odoi cross, and then a tangle between Young and Hudson-Odoi in the second half.
"I don't understand the reason and the decision of [referee] Anthony Taylor and VAR Stuart Attwell, because I see the images," Forest manager Nuno Espirito Santo told Sky Sports.
"It is hard to take. There is a penalty on Gio Reyna, it's a kick, don't tell me that is not contact. It's a penalty, then a handball, then the situation of the incident with Callum.
"So it's understandable that we react like this as a club because we want to get things right. We don't want bad referees. We want good decisions. OK, if we lost the game today and there were no incidents, we take it."
Forest had former referee Mark Clattenburg working at the club at the time as their referee analyst. He published a column in the Daily Mail defending the club's response and called the decisions a "hat trick of howlers."
He wrote: "One of these errors would have been bad enough. Three was a joke, and that is why Nottingham Forest were left feeling victimised after another defeat in which zero big decisions went their way.
"In a season where they have had to endure some egregious refereeing, this trip to Everton was as grim a game as they have encountered since returning to the Premier League.
"These situations were precisely why video technology was brought into the Premier League and yet, Attwell did not send Taylor to his monitor. Not once. It was a hat-trick of howlers from the refereeing team and, unfortunately for Forest, a continuation of an unjust trend that has hampered their survival fight.
"You will have seen the statement released by the club - how the PGMOL were contacted to warn that it was not appropriate for a Luton fan such as Attwell to play such a pivotal role in a massive match that would impact the relegation race."
Clattenburg left his role as Forest's refereeing consultant amid a backlash to his public interventions as a former Premier League referee.