The loss left Forest 17th in the standings with 26 points, four behind 16th-placed Everton who have a game in hand. Luton Town are one place and one point below Forest in the standings.
Forest were angered at being denied three penalty claims and minutes after the game issued a statement on social media platform X accusing Video Assistant Referee (VAR) Stuart Attwell of being a Luton fan.
Former Premier League referee Mark Clattenburg, who works for Forest as a referee analyst, described the decisions as a "joke."
"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," Clattenburg wrote in the Daily Mail.
Former Manchester United defender Gary Neville called on Clattenburg to resign from his position at Forest.
"If he saw those words go out which question the integrity of a referee and claims someone is a cheat for supporting another club, then he's supporting what is being said," Neville told Sky Sports.
"The statement is like a petulant child. It's embarrassing."
In a column for the Telegraph, former English referees chief Keith Hackett said there was no doubt Forest had good reason to be frustrated by the decisions that went against them.
"That said, there are ways to express your concerns and disappointment and on reflection, Nottingham Forest may perhaps feel they could have gone about it in a better way," Hackett added.
