title: Missing subnet referenced 'GatewaySubnet' in virtual network 'MyNetwork'
body: <p>I've built a network in Azure that contains two subnets, Back and Front.</p>
  
  <p>I'm now trying to create a gateway using Set-AzureVNetConfig but I'm getting a missing subnet called GatewaySubnet. This word does not exist anywhere in my scripts and Googling the word returns no results so it cannot be a reserved word.</p>
  
  <pre><code>&lt;NetworkConfiguration xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns="http://schemas.microsoft.com/ServiceHosting/2011/07/NetworkConfiguration"&gt;
  &lt;VirtualNetworkConfiguration&gt;
    &lt;Dns /&gt;
    &lt;LocalNetworkSites&gt;
      &lt;LocalNetworkSite name="lnt"&gt;
        &lt;AddressSpace&gt;
          &lt;AddressPrefix&gt;10.55.10.0/24&lt;/AddressPrefix&gt;
        &lt;/AddressSpace&gt;
        &lt;VPNGatewayAddress&gt;1.2.3.4&lt;/VPNGatewayAddress&gt;
      &lt;/LocalNetworkSite&gt;
    &lt;/LocalNetworkSites&gt;
    &lt;VirtualNetworkSites&gt;
      &lt;VirtualNetworkSite name="net" AffinityGroup="ag"&gt;
        &lt;AddressSpace&gt;
          &lt;AddressPrefix&gt;10.10.0.0/16&lt;/AddressPrefix&gt;
        &lt;/AddressSpace&gt;
        &lt;Subnets&gt;
          &lt;Subnet name="Front"&gt;
            &lt;AddressPrefix&gt;10.10.1.0/24&lt;/AddressPrefix&gt;
          &lt;/Subnet&gt;
          &lt;Subnet name="Back"&gt;
            &lt;AddressPrefix&gt;10.10.2.0/24&lt;/AddressPrefix&gt;
          &lt;/Subnet&gt;
        &lt;/Subnets&gt;
        &lt;Gateway&gt;
          &lt;ConnectionsToLocalNetwork&gt;
            &lt;LocalNetworkSiteRef name="lnt" /&gt;
          &lt;/ConnectionsToLocalNetwork&gt;
        &lt;/Gateway&gt;
      &lt;/VirtualNetworkSite&gt;
    &lt;/VirtualNetworkSites&gt;
  &lt;/VirtualNetworkConfiguration&gt;
  </code></pre>
  
  <p></p>
  
  <p>Why does Azure think my config file is missing a subnet called GatewaySubnet?</p>