[Windows] Preferences - Network
To open your preferences, click your avatar at the bottom left of the Tuple popover and select Settings from the dropdown:
You can also use the keyboard shortcut ctrl+,. This will bring up the settings window. You can then select the Network tab:
Force TURN
Enabling this will force your calls to use a TURN server. This is useful if you're a network that has known P2P issues
Force Media Server
Enabling this will force Tuple to use a media server for screen sharing. Again, useful on networks with known P2P issues.