Still seeing some errors with folks behind authenticated proxies. I'm seeing HTTP 407s and 401s. If you're behind an authenticated proxy, do let us know at http://support.myechoapp.com.
I've just released myEcho for Windows 22.214.171.124 to fix (I hope) this very issue. We will use your default credentials and the IE system configured proxy.
Let us know if you have trouble, and thanks for supporting myEcho!