Hi,
I think it has started to throw an error on restart.

I think maybe if a player leaves it until very late to leave....

[SmoothRestart] Server will restart in 30 seconds!
Failed to run a 10.00 timer in 'SmoothRestart v1.2.5' (NullReferenceException: Object reference not set to an instance of an object) at Oxide.Plugins.SmoothRestart+UIObject.Destroy (BasePlayer player) [0x00019] in <bf467d4cb71e41b283f4d4de5919e003>:0
at Oxide.Plugins.SmoothRestart+<UIMessage>c__AnonStorey1.<>m__2 () [0x00000] in <bf467d4cb71e41b283f4d4de5919e003>:0
at Oxide.Core.Libraries.Timer+TimerInstance.FireCallback () [0x00018] in <cf88a28c7fb44d36890d85a78331cc9d>:0
[SmoothRestart] Server will restart in 20 seconds!
[SmoothRestart] Server will restart in 10 seconds!
[SmoothRestart] Server will restart in 5 seconds!
[SmoothRestart] Server will restart in 4 seconds!
[SmoothRestart] Server will restart in 3 seconds!
[SmoothRestart] Server will restart in 2 seconds!
[SmoothRestart] Server will restart in 1 seconds!

It tries to hide UI but seems like the player is not online anymore indeed, and it caused the error. Destroy method could check if player or their connection is null.

Programming for rust is like trying to hold congee in your hands

yep... no null check for player in "UIMessage" or in destroy