IN CASE OF A PROXY WHILE UPLOADING YOUR VHD TO WINDOWS AZURE USING POWERSHELL
Sometimes when you are trying to do certain process on Windows Azure via Powershell you receive an ambiguous error with no specific error message, make sure that you don’t have a proxy in the environment blocking your communication to Windows Azure, If you do have one, then run the below command and then retry what you were doing before, it should work.
this is basically a .net code that is taking your credentials and passing it on to the proxy while executing your commands.
[System.Net.WebRequest]::DefaultWebProxy.Credentials = [System.Net.CredentialCache]::DefaultCredentials