Sometimes SwyxIT! over a VPN connection only gives one way media streaming. Disabling QOS resolves this issue.
Try the following registry key on the machine to force SwyxIt! not to use QoS:
HKLM\Software\Swyx\Client Line Manager\CurrentVersion\Options
UseQos
DWORD, Enable (1) / Disable (0) Quality of Service, default: 1 (enabled)
Set it to "0" and restart your SwyxIt!
Have a look at this link for more info and further links: