Teams Relay
Re-broadcast a live Microsoft Teams meeting or Town Hall to selected — or all — of your screens, full-screen, until you stop it.
Teams Relay re-broadcasts a live Microsoft Teams meeting or Town Hall to selected — or all — screens, full-screen, overriding whatever those screens are currently showing until you stop it. It uses Teams’ own RTMP-Out (“Custom Streaming”) feature to get the meeting’s video out — TheiaCast never joins the meeting itself, and no extra hardware or encoder is needed on the organizer’s side. This works with both regular Teams meetings and Town Hall/events (not the legacy “Live Events” product, which Microsoft retired).
Before you start: a one-time Teams admin step
A Microsoft 365 admin must turn on live streaming for your tenant, once: Teams admin center → Meetings → Meeting policies → the relevant policy → Audio & video → Live streaming → On. See Microsoft’s own docs: Allow live streaming with RTMP-Out and Broadcast audio and video from Teams with RTMP.
Microsoft 365 licence requirement. Microsoft doesn’t publish an explicit licence-tier table for RTMP-Out, but real-world testing found it gated in practice: on a Microsoft 365 Business Premium-only tenant, the organizer saw “You don’t have streaming permissions” in the Custom Streaming app even with Live Streaming already turned on for their policy. Assigning the organizer an Enterprise-tier licence (E3 or higher) resolved it. Treat this as a real, confirmed constraint even though Microsoft doesn’t spell it out in the docs linked above.
Starting a relay
- From the Devices page, click Teams Relay.
- Optionally give the session a label (e.g. “All-Hands Town Hall”) — this just helps you and other admins tell sessions apart, it isn’t shown on the devices themselves.
- Choose which devices to target using the tag and device group chips, the same selector used for Broadcast — leave everything unselected to target every device.
- Click Start Relay. TheiaCast generates a one-time RTMP Server URL and Stream Key and shows them in a details panel.
- Hand those two values to whoever is running the Teams meeting. In the meeting, they add the Custom Streaming app and paste the Server URL and Stream Key into it.
- Once Teams starts streaming, the status pill changes from Waiting for Teams to connect to Live, and targeted devices switch over to the meeting automatically.
💡 The RTMP Server URL and Stream Key are only ever shown once, in that details panel, right after starting. If you close the panel and need them again, reopen it with the Details button next to the status pill — but if someone else started the session, or the credentials were never copied down, you can’t get them back; stop the session and start a new one instead.
While a relay is active
- Targeted screens show the live meeting, muted by default, until the session ends — normal playlist rotation is paused, not lost; it resumes exactly where it left off.
- A device that was offline when the relay started picks it up automatically as soon as it reconnects — you don’t need to restart the session.
- If Teams’ stream drops momentarily (a network blip, the organizer reconnecting), the status pill shows Dropped, but targeted screens keep waiting rather than reverting to their normal playlist — this is usually temporary and resolves on its own once Teams reconnects.
- Only one Teams Relay session can be active at a time. If another admin already started one, starting a new one shows who started it and offers Take over anyway rather than silently replacing it.
Stopping a relay
Click Stop Relay from either the top bar or the details panel. Targeted devices return to their normal playlist immediately. A session left running with no admin action self-expires after 30 minutes if Teams never actually connects (e.g. the credentials were never pasted in).
Troubleshooting
| Symptom | Cause / fix |
|---|---|
| Status never leaves “Waiting for Teams to connect” | Double-check the Server URL and Stream Key were pasted into Teams’ Custom Streaming app exactly as shown (no extra spaces), that your Teams admin has turned Live Streaming on for your tenant, and that your network allows outbound RTMP on port 1935 from wherever the meeting is being streamed from |
| Teams shows “You don’t have streaming permissions” | This is Microsoft’s own permission check, not a TheiaCast error. Check the organizer is on the Teams desktop client, their actual effective policy via PowerShell (Get-CsOnlineUser — the admin center can show “Global” while a different system policy is really assigned), and that they have an Enterprise-tier (E3+) Microsoft 365 licence — see above |
| A specific device shows nothing | Check it was actually included in the target selection (tags/groups) when the session was started, and that it’s online — a device that reconnects after being offline picks up the relay automatically |
| A device that reconnected mid-relay shows its normal playlist instead | The device’s catch-up should happen automatically, but a page that continuously pulls live video can time out its own load check on some client builds and fall back to a holding screen — restarting (or rebooting) the device again is the workaround for now. Start relays to screens that are already on rather than ones mid-reboot |
| “Already active” when starting a new session | Someone else (or you, from another tab) already has a Teams Relay running — stop that one first, or use Take over anyway if you’re sure you want to replace it |
Requirements
Teams Relay is available on every tier — it isn’t gated behind a paid TheiaCast licence. It does require your organization’s Microsoft 365 admin to enable Teams live streaming, and an Enterprise-tier (E3+) Microsoft 365 licence for whoever starts the stream from the Teams side — both entirely on Microsoft’s side and unrelated to any TheiaCast licence.
Need Help?
Email [email protected] for help.
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