Failed to call hook 'OnLootEntity' on plugin 'SortButton v2.0.2' (InvalidCastException: Null object cannot be converted to a value type.)
  at System.Convert.ChangeType (System.Object value, System.Type conversionType, System.IFormatProvider provider) [0x00029] in <fb001e01371b4adca20013e0ac763896>:0 
  at System.Convert.ChangeType (System.Object value, System.Type conversionType) [0x0000c] in <fb001e01371b4adca20013e0ac763896>:0 
  at Oxide.Core.Plugins.Plugin.Call[T] (System.String hook, System.Object[] args) [0x00008] in <157a94ee66ab4a7991faecd1eb84be3b>:0 
  at Oxide.Plugins.SortButton.IsFriend (System.String playerId, System.String targetId) [0x00021] in <b1fec1d6b0ef490dbafd1968d2a0c7db>:0 
  at Oxide.Plugins.SortButton.IsAlly (System.UInt64 playerId, System.UInt64 targetId) [0x0003f] in <b1fec1d6b0ef490dbafd1968d2a0c7db>:0 
  at Oxide.Plugins.SortButton.HandleOnLootEntity (BasePlayer basePlayer, StorageContainer entity, System.Boolean delay) [0x000cc] in <b1fec1d6b0ef490dbafd1968d2a0c7db>:0 
  at Oxide.Plugins.SortButton.OnLootEntity (BasePlayer basePlayer, StorageContainer entity) [0x00000] in <b1fec1d6b0ef490dbafd1968d2a0c7db>:0 
  at Oxide.Plugins.SortButton.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x002f9] in <b1fec1d6b0ef490dbafd1968d2a0c7db>:0 
  at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <23ba99f131254889867c71f0bd137b1d>:0 
  at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in <157a94ee66ab4a7991faecd1eb84be3b>:0 
  at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <157a94ee66ab4a7991faecd1eb84be3b>:0 

Do you have the Friends plugin installed? Or perhaps a different plugin by the same name? Or a customized version of that plugin? According to the error, Oxide found a plugin named "Friends" and tried to call the "HasFriend" method using the signature bool HasFriend(string playerId, string friendId) but that method does not exist.

ouch , i have before but now remove it , so i just need to disable  "false" for  "Use Friends"

Yes, disabling the friend sharing capability is one way to resolve this. You could also disable the ownership checks entirely, to allow players to use sort buttons on containers owned by other players regardless of the relationship between the players.

that work !! thank you so much