Attempt to automate GSA setup in Azure through Graph API

Hi,

Using https://developer.microsoft.com/en-us/graph/graph-explorer and signed in as a user with Applications, Network, NetworkPolicy, Global Secure Access Admin roles, I am trying to POST to 
https://graph.microsoft.com/beta/networkAccess/connectivity/remoteNetworks
using Payload Body

{

  "name": "Hello",

  "region": "norwayEast"

}
How come I get the HTTP response code 400 with

"code": "UnknownError",

"message": "{\"error\":\"Invalid request parameters\"}",
?