How many years have Manchester United not entered the Champions League?

Manchester United didn't make it to the Champions League for a year. According to relevant public information, in the 36th round of Premier League, Manchester United lost to Brighton 0-4 away. After this campaign, Manchester United has decided to miss the top four this season, and missed the Champions League for the first time in nearly three seasons. The last time Manchester United missed the top four in the league was in the 18- 19 season. In the following two seasons, Manchester United won the third and second place respectively. Manchester United have not entered the Champions League for one year this season.