Users have reported and we have confirmed a problem with the latest version of the Viscosity client on our service. It is appears to be a problem with the handshake while connecting to our service with the latest version. We are currently investigating the issue.
The problem is isolated to the newest version of the Viscosity client, and it spans both Windows and OSX.
For now, we recommend using the default OpenVPN client in Windows (we actually recommend it anyway in Windows) and the TunnelBlick open-source client for OSX.
We have contacted SparkLabs to try to identify the problem for a possible patch on their end.