Karius's career changed dramatically after Liverpool's 2017/18 UEFA Champions League final defeat to Real Madrid in Kyiv, when two costly errors contributed to a 3-1 loss. The German goalkeeper's mistakes allowed Karim Benzema and Gareth Bale to score, leaving him facing intense criticism as Jürgen Klopp's side missed out on a sixth European Cup. Liverpool responded by winning the Champions League the following season, beating Tottenham Hotspur 2-0 in Madrid, but Karius was no longer part of the squad after moving to Beşiktaş on loan in search of a fresh start.
Summary from source