Merge pull request #128110 from jeremywilley1024/patch-1

Add Note about connection dependencies

Author: v-regandowner

articles/virtual-network/virtual-network-manage-subnet.md

@@ -74,6 +74,14 @@ To do tasks on subnets, your account must be assigned to the [Network contributo
 | Microsoft.Network/virtualNetworks/subnets/joinViaServiceEndpoint/action | Enable a service endpoint for a subnet.     |
 | Microsoft.Network/virtualNetworks/subnets/virtualMachines/read          | Get the virtual machines in a subnet.       |
 
+> [!NOTE]
+> If attempts to add, change, or delete a subnet in your virtual network fail, ensure there are no connections to other resources that may block the action:
+> - Gateway connections
+> - Gateways
+> - IPs
+> - Virtual network peerings
+> - App Service Environment (ASE)
+
 ## Add a subnet
 
 # [Portal](#tab/azure-portal)