Seems there is something blocking Trucky from accessing the Internet or Internet is disconnected. Usually a full Trucky reinstall should fix this issue.
The leaderboards are an experimental feature. Points and level calculation come from data collected while using the Trucky Overlay and based on various metric like km driven on-job and free roaming, deliveries, etc.
Invites allow users to join your VTC without needing to apply. Each invite can be used once and has an expiration date. You can create multiple invites with different expiration times.
Leeroy