Speakers found, but no sound

Your rooms are listed, you press Cast, and nothing plays. The desktop app may say:

The speakers were found, but nothing is getting back from them. That is nearly always a VPN or a firewall: pause it, then ask again.

or “No speaker can be reached on this network. Firewalls and VPNs make a habit of this; pause yours.” The extension says the same under No reply from the speakers or No speaker can be reached, or, after Cast, No speaker began playing:

The audio was offered and no speaker began playing it. Check they play from the Sonos app, then try again.

Cause

Thaumic Cast does not push audio at a speaker. The app gives each speaker an address on your computer, and the speaker comes and fetches the audio from it. So finding the speakers is only half of it: they also have to be able to reach your computer. Two things usually stop them.

• A firewall on your computer turns the speakers away when they come for the audio.
• A VPN sends the app’s traffic somewhere the speakers cannot follow, or leaves the app telling the speakers an address on the VPN, which they cannot reach.

UPnP turned off in the Sonos app can look the same.

Fix

1. Pause the VPN, if you use one.

2. Let Thaumic Cast through the firewall: incoming TCP on ports 49400 to 49410, from your own network. On Windows, that is Private networks when Windows asks. The details for each system are in Firewall and ports.

3. Ask again. In the desktop app, select Ask again in Rooms, then start the cast again.

4. Still silent? Restart the app: Restart Thaumic Cast, in its Server view or in the tray menu. Then cast again.

If that does not do it, check that UPnP is on in the Sonos app: UPnP is off in the Sonos app.

Thaumic Cast Server on a machine with several networks

A server with a VPN, Docker or a second network card may tell the speakers the wrong one of its addresses. Set advertise_ip (or THAUMIC_ADVERTISE_IP) to the address the speakers can reach, and restart it. See Run Thaumic Cast Server.

Only one room is silent

If the other rooms play and one does not:

• Not answering under a room means that speaker has dropped off the network. Check it is switched on, or remove it from the cast.
• Check the room’s volume and mute in the cast’s card. A cast starts no louder than your start limit, and a room that was quiet stays quiet: see Volume and start level.
• A speaker with a fixed volume (one wired to an amplifier) shows Fixed. Turn the amplifier up instead.

Verify

The room’s card in the desktop app says Casting, and you can hear it.