Get this from time to time

Failed to run a 1800.00 timer in 'BGrade v1.1.6' (NullReferenceException: Object reference not set to an instance of an object)
at BasePlayer.SendConsoleCommand (System.String command, System.Object[] obj) [0x00000] in <59aa6e5a3e0a42cb98d816e5c91366f4>:0
at BasePlayer.ChatMessage (System.String msg) [0x00018] in <59aa6e5a3e0a42cb98d816e5c91366f4>:0
at Oxide.Plugins.BGrade+BGradePlayer.<UpdateTime>b__7_0 () [0x0002d] in <f78dfae3f35e439ea1f131e0860c38cc>:0
at Oxide.Core.Libraries.Timer+TimerInstance.FireCallback () [0x00018] in <15f61ddda771464d8246ebdce8ff4811>:0