(Troubleshooting) Orleans Silos fail to start with “Subnet null”

Today I encountered an error starting Orleans: System.ArgumentException: Hostname '' with subnet null and family InterNetwork is not a valid IP address or DNS name.

The issue was that the Express Emulator was selected in Visual Studio. The Full Emulator should be selected instead.OrleansAzureSilos Subnet null - switch to the full emulator.

Here’s the full error text:

I’m posting this here for posterity, let me know if it helps :)