list.clearPlayers() not working

[SamsoomYT]

java.lang.NoSuchMethodException: com.mojang.authlib.properties.PropertyMap.removeAll(java.lang.String)

^^^^^ The error that shows

[19:51:31 WARN]: at java.lang.Class.getDeclaredMethod(Unknown Source)
[19:51:31 WARN]: at rip.northings.practice.tab.ReflectionUtil.getMethod(ReflectionUtil.java:277)
[19:51:31 WARN]: at rip.northings.practice.tab.ReflectionUtil.invokeMethod(ReflectionUtil.java:147)
[19:51:31 WARN]: at rip.northings.practice.tab.ReflectionUtil.invokeMethod(ReflectionUtil.java:124)
[19:51:31 WARN]: at rip.northings.practice.tab.PlayerList$1.callBack(PlayerList.java:513)
[19:51:31 WARN]: at rip.northings.practice.tab.Skin$3$1.run(Skin.java:171)