failed to call on hook

Failed to call hook 'OnServerSave' on plugin 'StaticLootables v2.8.2' (NullReferenceException: Object reference not set to an instance of an object)
at Oxide.Plugins.StaticLootables.SaveContainer () [0x00006] in <3d260956454b45e4be3000d154c40e7f>:0
at Oxide.Plugins.StaticLootables.OnServerSave () [0x00000] in <3d260956454b45e4be3000d154c40e7f>:0
at Oxide.Plugins.StaticLootables.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x0034d] in <3d260956454b45e4be3000d154c40e7f>: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

Keep getting this, have to delete the plugin and add it again, then it works fine for 1 day and i get the same problem