On screen: RTC Connecting, or a red No Route, in the voice panel
This error is produced locally. It does not appear because the service is down, so the fixes below are worth working through in order.
Discord voice is WebRTC over UDP to a regional voice node. RTC Connecting means the signalling connection is up and the media handshake is in progress. No Route means your client could not reach the voice server's address over UDP at all.
Discord itself draws the line for you. Their support page groups ICE Checking, No Route, RTC Connecting and Connecting together and says: “These errors generally mean there's something interfering with the connection on your end -- like a firewall or possibly a VPN.” The server-side counterpart has different wording.
If the panel says Waiting for Voice Server, that one is Discord's — their page says you should not see it unless they are having trouble. Anything in the RTC Connecting or No Route family is on your side of the wire.
Operator documentation: support.discord.com. Discord's page is the clearest official statement of the client-versus-server split we have found anywhere, which is why we quote it directly above.
Discord voice is WebRTC over UDP to a regional voice node. RTC Connecting means the signalling connection is up and the media handshake is in progress. No Route means your client could not reach the voice server's address over UDP at all.
This error is produced locally. It does not appear because the service is down, so the fixes below are worth working through in order.
Start with: Change the voice region. Channel Settings, Overview, Region Override. This is the most effective step and it is buried in every other guide. No Route usually means one specific regional node is unreachable from your ISP — moving to another region sidesteps it entirely.