Got this error and the server crashed...

Receiving unhandled NULL exception
#0  0x0055c3741a2760 in std::pow(float, float)
#1  0x0055c373e8f31e in std::pow(float, float)
#2  0x0000004241472e in (wrapper managed-to-native) UnityEngine.Transform:get_position_Injected (UnityEngine.Transform,UnityEngine.Vector3&)
#3  0x00000042784058 in RustIO.Interface/B:A (object,System.Timers.ElapsedEventArgs)
#4  0x000000424ff873 in System.Threading.Timer/Scheduler:TimerCB (object)​

Any ideas what could be the problem

Looks like the Rust:IO extension.

Appreciate it, thanks. I assume updating Rust:IO would repair this? 

Just remove it, it's useless bloatware at the moment imo.