Why does Microsoft Edge open some local websites, but not others, where the domain name is routed to 127.0.0.1 in hosts file

Question

Your network can block loopback as a security measure in Windows 10.
Open a command prompt as administrator, and run this to exempt Edge from a loopback:
```
CheckNetIsolation LoopbackExempt -a -n="Microsoft.MicrosoftEdge_8wekyb3d8bbwe"
```

(Microsoft.MicrosoftEdge_8wekyb3d8bbwe is the identifier for the Edge app)

There’s a blog post here giving more detail:
https://blogs.msdn.microsoft.com/msgulfcommunity/2015/07/01/how-to-debug-localhost-on-microsoft-edge/