Solve my HMA Pro VPN Error

HMA! Pro VPN version: 2.8.24.0

Installed versions of .NET framework:
v2.0.50727 2.0.50727.4927 SP2
v3.0 3.0.30729.4926 SP2
v3.5 3.5.30729.4926 SP1
v4
Client 4.5.50709
Full 4.5.50709
v4.0
Client 4.0.0.0
4.5

=================== Exception message: ===================

HMA_CLIENT_ENGINE.EnumerationValueNotValidException: ConnectingFailedReason
at HMA_CLIENT_ENGINE.StateConnecting.HandleEvent(ConnectingFailedEvent e)
at HMA_CLIENT_ENGINE.ConnectingFailedEvent.AcceptHandler(HMAClientEventHandler hmaClientEventHandler)
at HMA_CLIENT_ENGINE.HMAClientStateMachine.a(HMAClientEvent A_0)
at HMA_CLIENT_ENGINE.HMAClientStateMachine.a(Object A_0)
at HMAGUI_CSHARP.Dispatcher.a.b(Object A_0)

Above is the error that I am getting since yesterday on my HMA Pro VPN. I am using Windows 7 and I have tried everything I could to get rid of this error.

Please help me.