diff --git a/specification/network/resource-manager/Microsoft.Network/stable/2019-02-01/virtualWan.json b/specification/network/resource-manager/Microsoft.Network/stable/2019-02-01/virtualWan.json
index 3c18a69662a0..ff0c5cf24082 100644
--- a/specification/network/resource-manager/Microsoft.Network/stable/2019-02-01/virtualWan.json
+++ b/specification/network/resource-manager/Microsoft.Network/stable/2019-02-01/virtualWan.json
@@ -2484,6 +2484,9 @@
           "description": "The sas-url to download the configurations for vpn-sites"
         }
       },
+      "required": [
+        "outputBlobSasUrl"
+      ],
       "description": "List of Vpn-Sites"
     },
     "VirtualHubProperties": {