If you notice multiple routing events noted as Gladly Voice browser connection failed in the Conversation Timeline, a bad webrtc state is typically the issue that prevents receiving calls.
What is webrtc?
In short, webrtc allows voice and video to be transmitted over a browser. All modern browsers have this technology built-in, which Gladly utilizes to transmit Voice services.
If webrtc gets stuck in a "bad state" (similar to a computer freezing or not responding), this prevents Gladly from properly communicating with telecom services. Gladly will try to connect multiple times, resulting in numerous routing events, as mentioned above. Restarting the browser usually resolves the issue.