Object reference not set to an instance of an object

Failed to call hook 'OnPlayerDeath' on plugin 'RustRewards v3.1.0' (NullReferenceException: Object reference not set to an instance of an object)
  at Oxide.Plugins.RustRewards.GiveReward (BasePlayer player, Oxide.Plugins.RustRewards+RewardType type, System.Double amount, BaseEntity ent, System.String weapon, System.Single distance, System.String name) [0x00567] in <a096f223dbe045cda53b4ae0fb10acb0>:0 
  at Oxide.Plugins.RustRewards.OnPlayerDeath (BasePlayer player, HitInfo info) [0x00159] in <a096f223dbe045cda53b4ae0fb10acb0>:0 
  at Oxide.Plugins.RustRewards.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x0038d] in <a096f223dbe045cda53b4ae0fb10acb0>:0 
  at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <09575a60985045248bcb43b20faeeb99>:0 
  at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in <d5f57e12edfe4fa0b5c5dbdd9b51eff8>:0 
  at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <d5f57e12edfe4fa0b5c5dbdd9b51eff8>:0 

Got thi error today at 5am. Wasn't online to see it happen. 

Seeing the same issue here for Killing BotReSpawn NPCs:

[Death Notes] Flint Monkey rubbed out Comcast Neil Armstrong with a HMLMG from 10 meters away. 
Failed to call hook 'GiveRustReward' on plugin 'RustRewards v3.1.0' (NullReferenceException: Object reference not set to an instance of an object)
  at Oxide.Plugins.RustRewards.GetMultiplier (BasePlayer player, System.String weapon, System.Single distance, BaseEntity ent) [0x00044] in <0a08a7a779ed4b029bbc1e70c00a8400>:0 
  at Oxide.Plugins.RustRewards.GiveReward (BasePlayer player, Oxide.Plugins.RustRewards+RewardType type, System.Double amount, BaseEntity ent, System.String weapon, System.Single distance, System.String name) [0x0005d] in <0a08a7a779ed4b029bbc1e70c00a8400>:0 
  at Oxide.Plugins.RustRewards.GiveRustReward (BasePlayer player, System.Int32 type, System.Double amount, BaseEntity ent, System.String weapon, System.Single distance, System.String name) [0x00000] in <0a08a7a779ed4b029bbc1e70c00a8400>:0 
  at Oxide.Plugins.RustRewards.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x00f66] in <0a08a7a779ed4b029bbc1e70c00a8400>:0 
  at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <09575a60985045248bcb43b20faeeb99>:0 
  at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in <d5f57e12edfe4fa0b5c5dbdd9b51eff8>:0 
  at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <d5f57e12edfe4fa0b5c5dbdd9b51eff8>:0  

Will do.