title: NuGet Error: SecureChannelFailure (Object refence not set to an instance of an object)
body: <p>I'm using Monodevelop on ubuntu and it seems as though the NuGet package manager extension is not working. When I check the sources I get the following error for <a href="https://api.nuget.org/v3/index.json" rel="nofollow noreferrer">https://api.nuget.org/v3/index.json</a></p>
  
  <pre><code>Error: SecureChannelFailure (Object refence not set to an instance of an object)
  </code></pre>
  
  <p>I've installed via flatpak.</p>