I have the same problem. I am using Microsoft Outlook. My internetprovider is Ziggo.
The error message is:
Send test e-mail message: Outlook cannot connect to your outgoing (SMTP) e-mail server. If you continue to receive this message, contact your server administrator or Internet service provider (ISP).
In the settings for Email under “Connection” and under “Modem” there is a line filled in with info: “GOOSEVPN” , but this part is grayed out.
By choosing “Connect via modem when Outlook is offline” , it is no more grayed out and you can change settings for the Modem.
Under Modem properties there is a host-name already filled in: be-4.goosevpn.com with option to choose for “first choose an other connection” .
What other connection could you fill in?