This guide explains how to deploy The Layer for Outlook add-in to users in your Microsoft 365 tenant.
You must be a Global Administrator, or have an Office Apps Administrator / Exchange Administrator role with permission to deploy Integrated apps.
Prerequisites
Before you begin, you'll need:
A Microsoft 365 tenant with Exchange Online mailboxes
Global Administrator or equivalent access to Microsoft 365 Admin Center
Users running a supported version of Outlook:
Outlook on the web
New Outlook for Windows
Outlook for Mac
Outlook mobile
Classic Outlook for Windows via Microsoft 365
The Layer manifest URL:
Step 1 — Open Integrated apps
Go to Microsoft 365 Admin Center and sign in as an administrator.
From the left-hand navigation, select Settings → Integrated apps.
If you don't see Integrated apps, select Show all first.
Step 2 — Upload The Layer add-in
Select Upload custom apps.
For App type, select Office Add-in.
Choose Provide link to manifest file.
Enter:
Select Validate.
Microsoft should confirm that the manifest is valid.
Using a manifest file instead
If you've been provided with the XML file directly, you can choose Upload manifest file (.xml) and upload the supplied manifest.xml file instead.
Step 3 — Assign users
Choose who should receive The Layer add-in:
Just me — useful for testing before a wider rollout
Specific users/groups — assign the add-in to selected users, a mail-enabled security group or Microsoft 365 group
Entire organization — deploy the add-in to everyone in your tenant
We recommend deploying to a small number of test users first.
Once you've selected the users, click Next.
Step 4 — Review permissions and capabilities
Review the permissions requested by The Layer.
The add-in requests Read/Write Mailbox access. This enables The Layer to interact with the currently open email or appointment and sync relevant content with The Layer CRM.
Review the services the add-in connects to, including:
outlook.thelayer.comThe Layer API
Click Next.
Select Finish deployment.
Click Done.
Step 5 — Allow the deployment to propagate
Once deployment is complete, The Layer should show as Deployed within the Integrated apps list.
Microsoft advises that deployment can take up to 6–12 hours, although the add-in will often appear much sooner.
Users may need to fully restart Outlook before The Layer appears.
Step 6 — Verify the add-in
Once the deployment has reached the user:
Open Outlook.
Open any email.
Look for The Layer in the message toolbar or ribbon.
In Outlook on the web or New Outlook, you may also find it under Apps or the ••• menu.
Select The Layer.
The Layer task pane will open on the right-hand side.
Sign in using your The Layer CRM credentials.
Once authenticated, the CRM panel will load.
Optional — Pin The Layer
The Layer supports Outlook's task pane pinning functionality.
This allows users to keep The Layer open while moving between emails.
To enable it:
Open The Layer task pane.
Select the pin 📌 icon at the top of the pane.
The Layer will remain open as the user moves between supported Outlook items.
Managing the add-in later
Change assigned users
Go to:
Microsoft 365 Admin Center → Settings → Integrated apps → The Layer → Users
You can then update the users or groups assigned to the add-in.
Remove The Layer
Go to:
Integrated apps → The Layer → Remove app
Updates
Most updates to The Layer for Outlook happen automatically and require no action from your Microsoft 365 administrator.
The application itself is hosted by The Layer, so code and behaviour updates are delivered automatically.
If The Layer releases a new manifest version, for example to introduce new Outlook buttons, capabilities or permissions, you may be asked to repeat the upload process using:
Troubleshooting
The Layer button doesn't appear
Try the following:
Fully restart Outlook
Sign out of Outlook and sign back in
Confirm the user is included in the deployment
If you've deployed to a group, confirm the user is a member of that group
Allow additional time for Microsoft 365 deployment to propagate
“Add-in could not be started”
Confirm that the following address is reachable from the user's network:
If it cannot be reached, contact The Layer support team.
The add-in is blocked by Microsoft 365 policy
Check that:
Integrated apps deployment isn't restricted by your organisation's Microsoft 365 policies
Your Exchange Online organisation settings permit the deployment model you're using
Your Microsoft 365 administrator may need to review your organisation's add-in policies.
Sign-in fails inside The Layer
Check that:
The user has valid The Layer CRM credentials
The Layer is accessible from the user's network
Your organisation's firewall or security policies aren't blocking access to The Layer
If the issue continues, contact The Layer support team.