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Guide

How to connect Microsoft 365 mailboxes to Instantly

Connecting a Microsoft 365 mailbox to Instantly takes under 30 seconds. You'll use Instantly's native Microsoft Office 365 / Outlook connection flow, which handles SMTP and OAuth in a single guided process. This guide walks through every step with screenshots.

Works with all Microsoft 365 and Outlook mailboxes
Takes under 30 seconds per mailbox
Uses SMTP + OAuth for a stable, authorized connection

Once your Microsoft 365 mailboxes are provisioned and DNS is configured, the next step is connecting them to your sending platform. Instantly supports native Microsoft 365 and Outlook connections through a straightforward OAuth flow.

The process below covers every screen from login to confirmation. Follow it once and the pattern repeats identically for every additional mailbox you connect.

Connecting your mailbox

Step 1
Log in to your Instantly account
Go to app.instantly.ai and sign in. Navigate to the Accounts page from the left sidebar.
Step 2
Click the "Add New" button
On the Accounts page, click the "Add New" button in the top right corner.Click the "Add New" button
Step 3
Select Microsoft Office 365 / Outlook
In the "Connect existing accounts" card, select "Microsoft Office 365 / Outlook" as the account type.Select Microsoft Office 365 / Outlook
Step 4
Confirm SMTP is enabled
Click the "Yes, SMTP has been enabled" button to proceed.Confirm SMTP is enabled
Step 5
Enter the mailbox email address
Type the full email address of the mailbox you're connecting, then click Next.Enter the mailbox email address
Step 6
Enter the mailbox password
Enter the password for that mailbox and click Next or Sign In to authenticate.Enter the mailbox password
Step 7
Grant permission for Instantly
Consent on behalf of your organization and accept the permission request. Follow any remaining prompts to authorize Instantly to access your Microsoft account. Once complete, the mailbox will appear in your Accounts list as connected.Grant permission for Instantly
Where to go next

The most useful next step is usually either a deeper guide or a page that helps you compare provider fit.

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Frequently asked questions