What should I do if desktop seems connected, but there's no sound?

If you're using Chrome, please try Firefox instead. Chrome has some in-browser Voice-over-IP troubles with RINGR currently, which prevent it from connecting under some circumstances (related to network configuration) – this is the main reason we still have RINGR Desktop in beta status, actually. Firefox connects much more reliably, and should hopefully work. We're working on solving the Chrome issue and hope to have it figured out soon!