Outlook add-in support
How to install the Brandesk add-in for Outlook, and what to do if your signature does not appear. A question not answered here? Write to us at hello@brandesk.io.
1. Install the Outlook add-in
The add-in is installed once, for the whole organization, by a Microsoft 365 administrator (Exchange administrator or Global administrator). Employees install nothing: the add-in appears in their Outlook by itself.
Beforehand, your organization has connected Microsoft 365 to Brandesk (Directory sync menu) and assigned a published signature to its employees.
- In Brandesk, open Directory sync and copy the manifest address shown in the “Outlook add-in” card.
- Open the Microsoft 365 admin center, then Settings › Integrated apps. If Settings is not in the left menu, click “Show all” first.
- Click “Upload custom apps”. In “App type”, choose “Office Add-in”, then the option to provide the manifest URL. Paste the copied address, click “Validate”, then “Next”.
- Click “Add users”: yourself only to try it first, the groups of the employees who get a Brandesk signature, or “Entire organization”. A group nested in another group is not taken into account: choose top-level groups.
- Click “Next”, accept the permissions if Microsoft asks you to, then click “Finish deployment”. The add-in only asks to read and change the message being written, to add the signature to it.
Microsoft may take 24 to 72 hours to show the add-in in Outlook. As soon as a signature has been fetched, the Brandesk “Outlook add-in” card shows “In service”. How the add-in works is detailed on the Outlook signature page.
2. Your signature in Outlook
- New message: the signature is added by itself at the end of the message, within a few seconds. The Outlook signature is turned off for this message, so it never carries two signatures.
- Reply and forward: the reply signature is added, if your organization has one.
- “Signature” button, on computers and on the web (“Message” tab of the ribbon, or under “Apps”): it opens the Brandesk pane, which inserts the signature again with “Insert my signature”, offers your other signature languages and lets you sign in the first time.
The add-in works in Outlook on the web, Outlook for Windows (new and classic), Outlook for Mac, and Outlook on iPhone, iPad and Android.
3. The signature does not appear
Try these steps in order.
- Close and reopen Outlook, then write a new message. After a first deployment, Microsoft may take 24 to 72 hours to show the add-in.
- Insert it yourself: in the message, click “Signature” (“Message” tab, or under “Apps”), then “Insert my signature”.
- Sign in once if Outlook shows “Brandesk could not add your signature: sign in once…”: click “Sign in”, or “Insert my signature” in the pane. On iPhone, iPad and Android, the message asks you to sign in once with “Signature” in Outlook on a computer: do so, then write a new message on your phone.
- Read the reason shown in the Brandesk pane. Most are solved with your Brandesk administrator:
| Message in the pane | What to do |
|---|---|
| “Your Microsoft 365 organization is not linked to any Brandesk account.” | Check that you are signed in to Outlook with your work account. Otherwise, the administrator connects Microsoft 365 in Brandesk (Directory sync menu). |
| “This Microsoft 365 account matches no employee synced in Brandesk.” | The administrator checks that your account is among the synced users (Directory sync menu), then runs a sync again. |
| “Your employee record is not active in Brandesk.” | The administrator checks your record (Employees menu). An account disabled in Microsoft 365 is also disabled in Brandesk. |
| “No Brandesk signature is assigned to you yet.” | The administrator assigns you a published signature (Signatures › Assignment menu). |
| “Your Brandesk signature is installed another way than through this add-in.” | Your signature is set up for another installation method (Gmail, or copy from your Brandesk space). Check with the administrator. |
| “Your Brandesk signature is being installed, or its installation failed.” | Wait a few minutes, then write a new message. If the message remains, the administrator checks the Signatures › Installations menu. |
Known limits
- Calendar invitations do not get a signature.
- On iPhone and iPad, a message created from the “Share” menu gets no signature.
- On iPhone, iPad and Android, the add-in must have been deployed on or after October 24, 2026 (manifest version 1.1 or later). If it was deployed before, the administrator updates it in Integrated apps.
- Classic Outlook for Windows before version 2403 does not add the signature by itself: use “Insert my signature”.
- If your organization's conditional access requires “approved client apps”, the add-in cannot sign in.
4. Contact us
Write to hello@brandesk.io. We reply within two business days.
To speed things up, attach the add-in's diagnostic: on a computer, in the message concerned, open “Signature”, then the “Diagnostic” section, and click “Copy the diagnostic”. Paste it into your message, stating which Outlook you use (web, Windows, Mac, iPhone, iPad or Android).
The diagnostic stays in Outlook: Brandesk only receives it if you send it to us. The data used by the add-in is described in the privacy policy.