Sometimes VPN is stuck in Connecting... state indefinitely. Disconnecting, then connecting again to a randomized server fixes this.
However, if one uses VPN killswitch, your phone will basically be offline until you notice this. The Android's "always-on VPN disconnected" notification unfortunately does not fire as it doesn't consider Connecting... to be an issue. It would be nice to have an option to notify the user if such unconnectivity occurs, and also to auto-retry with another server in the same country.