When using Dual-Hub mode, the Hub status LEDs can provide some more information:

Solid orange / red
The Hub is working but the signal between the two Hubs is poor. Each Hub has an effective range of 50m (40m in the US), and both Hubs need to be able to talk to each other to allow for seamless handover of Headsets. Try moving the Hubs closer to improve the signal.

Blinking red
The network connection between the two Hubs is not available. Check the cable and ensure the switch or router is powered up and working.

In some cases local power or network issues can cause an error in one of the Hubs which interrupts communication for one or more Headsets. In this situation, the easiest way to get your Dual-Hub system up and running normally is to reset both Hubs by switching the power to each unit off, pausing for 5 seconds, and then switching it on again. Give the units a couple of minutes to reestablish communication and your Headsets should all be back on the same conference.

When connecting two charging Docks, check that the power cables are attached correctly and that the correct VoCoVo Link power supply has been used.