Turn idle Microsoft Teams Rooms into digital signage. When a room is between meetings, OptiSigns plays your assigned content — announcements, dashboards, branding, menus — right on the room display, and clears it the instant a meeting starts.

This guide covers the two ways to connect a Teams Room to OptiSigns, so you can pick the one that fits how your organization works.

Two ways to connect

	Signage URL · Recommended, fastest start	Service Principal
What it gives you	Get content on a room in minutes — no app registration.	OptiSigns discovers and lists all your Teams Rooms (model, online/offline, health) in one place.
Microsoft setup	None in Azure. You paste a URL in the Teams Rooms portal.	An Entra admin registers a read-only app and grants two permissions.
Best for	Getting started, a few rooms, or when you can't register an Azure app.	Managing a fleet of rooms and seeing their status alongside your other screens.
Who can set it up	A Teams Rooms admin.	A Microsoft Entra (Azure AD) admin, one time.

Important — read this first. Microsoft does not offer a way for apps to push content to Teams Rooms automatically. So with either method, the final step is a one-time manual paste of an OptiSigns signage URL into the Teams Rooms portal. The Service Principal method doesn't push content for you — it gives OptiSigns visibility into your rooms. Many teams use both: Service Principal to see every room, and Signage URLs to deliver the content.

What you'll need

An OptiSigns account on a plan that includes device management (MDM / room integrations), with the Owner or Super Admin role. Start a free trial — you only pay for rooms you activate signage on.
Microsoft Teams Rooms Pro. Digital signage is a Teams Rooms Pro capability — rooms on Teams Rooms Basic can't display signage.
At least one Teams Room that's online and signed in.
For the Service Principal method only: a Microsoft Entra (Azure AD) Global Administrator who can register an app and grant admin consent.

How it works

OptiSigns generates a secure signage URL for each screen you want to show on a room. Microsoft's Teams Rooms Pro platform has a built-in Digital signage feature that can display a custom URL while the room is idle. You paste the OptiSigns URL there once; from then on the room plays whatever you assign in OptiSigns, and updates are live.

When a meeting starts — or someone wakes the room — the display returns to the normal Teams Rooms UI automatically, and signage resumes when the room goes idle again. There's no impact on meeting quality, audio/video, or scheduled meetings.

Open the Teams Rooms page

In OptiSigns, open Devices in the top navigation, then in the left sidebar under Room Integrations, click Teams Rooms. If you haven't connected yet, you'll see the two methods side by side.

OptiSigns Teams Rooms — the two ways to connect: Signage URL (recommended) and Service Principal

Pick your method below.

Method 1 — Connect with a Signage URL (recommended)

No Azure setup. You'll mint a URL in OptiSigns, give it content, and paste it into the Teams Rooms portal.

Step 1 — Mint a Signage URL

On the Signage URL card, click Mint URLs (shown above).

In the New Signage URL dialog, give the URL a Name (for example, your room or location — Atlanta Lobby). The optional Target label is just a note to help you remember where you'll paste it; it doesn't control anything. Click Next.

The New Signage URL dialog — name the URL, then click Next

Step 2 — Assign content

Clicking Next creates the URL and opens the Signage URLs tab (the page now shows Connected · Signage URLs only). On the new row, click + Assign content.

In the Assign content dialog, choose a Content Type — Asset, Playlist, or Schedule — then pick the specific item to play. Click Save.

The Assign content dialog — pick a Content Type, choose the item, then Save

OptiSigns copies the new signage URL to your clipboard and shows the paste instructions. (You can reopen them any time with Show me how to paste on the Signage URLs tab.)

Step 3 — Paste the URL into the Teams Rooms portal

In the Paste your Signage URL in Teams Rooms portal dialog, click Open Teams Admin Portal. Then, in Microsoft's portal:

Sign in and open Digital signage.
Click Add source and give it a clear name (matching your room or group).
Choose Custom URL, paste the OptiSigns URL, then Review → Finish.
Select the new source → Assign to devices → pick your Teams Room(s) → Apply.

The paste-instructions dialog — copy the URL, then click Open Teams Admin Portal

Within about 30 seconds the room fetches the URL and your content appears during idle. Start a test meeting — content should clear instantly when the meeting connects.

Repeat Steps 1–3 to mint a URL for each room or room group. You manage all minted URLs (and reassign their content any time) under the Signage URLs tab.

Method 2 — Connect with a Service Principal

This connects a read-only Microsoft Entra app so OptiSigns can discover and list all your Teams Rooms automatically — model, online/offline status, and device health — alongside your other screens. (You'll still deliver content with a signage URL — see "Put content on a room" below.)

Do it in this order: register the app → grant admin consent → then connect OptiSigns. That isn't the intuitive order, and it matters. Test Connection validates your credentials, not your permissions, so it can pass on an app that hasn't been consented yet. On top of that, Microsoft caches access tokens for about an hour — connect before consenting and the cached token stays permission-less, so syncing keeps failing for up to an hour after you've actually fixed it. Consent first and you avoid both traps.

Step 1 — Register the application

Sign in to the Microsoft Entra admin center as a Global Administrator and go to Identity → Applications → App registrations → + New registration.

Name — anything you like; pick something a future admin will recognise, for example OptiSigns Teams Rooms.
Supported account types — Single tenant. Your rooms live in your own tenant.
Redirect URI — leave it blank. This app authenticates service-to-service, so there's no browser redirect.

Click Register.

Step 2 — Copy the two IDs

You land on the app's Overview page. Copy these two values — you'll paste them into OptiSigns at the end:

The app Overview page with Application (client) ID and Directory (tenant) ID highlighted

Application (client) ID
Directory (tenant) ID

Ignore the Object ID. OptiSigns doesn't use it, and it's easy to grab by mistake because it sits between the two you do need.

Step 3 — Add a permission

In the app's left menu, open API permissions → + Add a permission. In the panel that opens, choose Microsoft Graph.

The Request API permissions panel with Microsoft Graph selected

Step 4 — Application permissions, then TeamworkDevice.Read.All

Choosing Application permissions, then searching for and ticking TeamworkDevice.Read.All

When Microsoft asks "What type of permissions does your application require?", choose Application permissions — not Delegated permissions. Delegated means "act as the signed-in user", and there is no signed-in user here: OptiSigns reads your inventory as a background service. Choosing Delegated is the most common mistake, and it fails silently later.
In the search box, type TeamworkDevice.Read.All.
Tick its checkbox. The description reads Read Teams devices, and Admin consent required says Yes — that matters in the next step.
Click Add permissions.

TeamworkDevice.Read.All is the only required permission. You can optionally add CrossTenantInformation.ReadBasic.All, which lets OptiSigns display your tenant's name in the console — everything works without it.

Step 5 — Adding a permission is not the same as granting it

Your permission is now listed, but look at the Status column:

The permission list showing TeamworkDevice.Read.All with the status Not granted

⚠ Not granted for <your tenant>.

The permission has been requested, not approved. In this state Microsoft still issues OptiSigns an access token — it simply carries no privileges, so every attempt to read your rooms returns 403 Forbidden. Nothing about the app registration looks broken; it just doesn't work.

Click ✓ Grant admin consent for <your tenant> and confirm.

If that button is greyed out, your account isn't a Global Administrator or Privileged Role Administrator. You'll need someone who is — an app can't consent to itself.

Step 6 — Confirm the consent took

Give it a moment, then check the Status column again. This is what correct looks like:

The permission list showing Granted for the tenant, with green check marks

A green banner reading "Successfully granted admin consent for the requested permissions", and TeamworkDevice.Read.All showing Granted for <your tenant>.

Don't move on until you see it. Consent takes about a minute to propagate.

Step 7 — Create a client secret

Open Certificates & secrets → Client secrets → + New client secret. Give it a description and an expiry, then Add.

The client secret row, with the Value column highlighted next to the Secret ID

Copy the Value — the long string in the Value column. Not the Secret ID beside it. The two sit side by side and look equally cryptic, and pasting the Secret ID is the second most common mistake here.

Microsoft shows the Value once. Navigate away without copying it and it's gone for good — you'll have to delete the secret and create a new one. Note the expiry date too: when a secret expires the connection stops working, and the fix is a new secret plus a reconnect.

Step 8 — Connect it in OptiSigns

Back on the OptiSigns Teams Rooms page, on the Service Principal card, click Add Service Principal.

The Add Microsoft Service Principal dialog filled in, showing Connection successful

Fill in four fields:

Name — any label you'll recognise (for example, Contoso Teams SP)
Application (client) ID — from Step 2
Directory (tenant) ID — from Step 2
Client Secret — the Value from Step 7

Click Test Connection. OptiSigns validates the credentials against Microsoft Graph and shows Connection successful — then Save lights up. Click Save.

Within a few minutes your Teams Rooms appear in the Devices tab, each with its model and live online/offline status.

Put content on a room

Discovering rooms doesn't put content on them — that still uses a signage URL. From the Signage URLs tab, click New Signage URL and follow Method 1, Steps 1–3 above to mint a URL, assign content, and paste it into the Teams Rooms portal for that room.

Licensing

Activating signage on a Teams Room uses one screen license from your OptiSigns pool — the same licenses you use for any other screen. Discovered rooms that you haven't activated are free; you're only billed for rooms you turn signage on for. See full pricing →

Troubleshooting

My rooms show signage, but OptiSigns lists no devices. Expected — and it tells you exactly where the problem is. Signage delivery uses the signage URL and never touches Microsoft Graph; device inventory uses the Service Principal and does. Signage working proves nothing about the Service Principal. Go to Step 5 above and check the Status column on the app's API permissions page.

The sync failed, or the connection shows "Reconnect required". Behind the scenes Microsoft is returning:

403 Forbidden — Missing role permissions on the request.
API requires one of 'TeamworkDevice.Read.All, TeamworkDevice.ReadWrite.All'.
Roles on the request ''.

Read that last part — Roles on the request '' — as: the token is valid and it carries no permissions. Your client ID, tenant ID and secret are all fine. Either admin consent is missing, or the permission was added under Delegated instead of Application. Fix it in three steps, and do all three:

In Entra, confirm TeamworkDevice.Read.All sits under Application permissions, then click Grant admin consent and wait for the green check.
In OptiSigns, click Disconnect on the Teams Rooms page.
Click Add Service Principal again and re-enter the same three values.

Step 3 isn't optional: a connection that has failed is parked in an errored state, and fixing the permission in Entra doesn't reach back and revive it. Reconnecting is what puts it back to work.

"Test Connection" passed, but the sync still fails. Two possibilities. Either consent came after the connection — access tokens are cached for about an hour, so a token minted before consent stays permission-less until it expires; grant consent, reconnect, and if it still fails wait an hour and retry. Or the permission is Delegated rather than Application — check the Type column on the API permissions page; it must read Application.

"Test Connection" fails with "Invalid client credentials." Re-check the Application (client) ID, Directory (tenant) ID, and Client Secret — copy them exactly from the Entra app, and make sure you copied the secret's Value, not its Secret ID. If the secret has expired, create a new one in Certificates & secrets and paste the new value.

"No Teams Rooms found in your tenant." If the connection is healthy — no "Reconnect required" badge and the Sync now button is clickable — this means what it says: Microsoft Graph returned zero signage-eligible rooms. In the Teams admin center, confirm you have Teams Rooms devices enrolled and that they carry a Teams Rooms Pro license. If the connection shows Reconnect required and Sync now is greyed out, ignore this message — the sync never ran; see the entry above.

I pasted the URL but nothing shows on the room. Confirm the room is online and licensed for Teams Rooms Pro (Basic doesn't include digital signage). Make sure you pasted the full URL (it begins with https://) as a Custom URL source, and that the source is assigned to that device in the Teams Rooms portal.

Content shows but doesn't clear when a meeting starts. This is controlled by the Teams Rooms digital-signage setting in Microsoft's portal — confirm signage is set to display only while the room is idle.

The Teams Rooms portal says the URL is invalid. The URL may have been truncated on copy. Return to the OptiSigns Signage URLs tab, click Copy on that URL again, and re-paste.

Need help?

Email: support@optisigns.com
More guides: support.optisigns.com
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