Airmail Keeps Asking You to Sign In to Microsoft, or the Microsoft Sign-In Window Opens Blank

Some users with a Microsoft account (Outlook.com, Hotmail, Live, Microsoft 365 or a work or school account) report one of these symptoms in Airmail:

Airmail asks you to sign in to Microsoft every time you open the app.
A dialog appears saying that Airmail wants to use "login.microsoftonline.com" to sign in.
When you add the account, the Microsoft sign-in window opens completely blank and never loads.
After signing in, messages appear duplicated in the message list.

All of these come from the same cause: the Microsoft sign-in session (the OAuth token) stored for your account is no longer valid, so Airmail has to ask Microsoft for a new one. The steps below resolve it without any Terminal command, third-party tool or additional system permission.

The dialog about login.microsoftonline.com is normal

Microsoft accounts do not use a password inside the app. They use a secure sign-in page hosted by Microsoft. macOS and iOS always ask for your consent before an app opens that page, which is why you see the message about "login.microsoftonline.com". You can safely choose Continue: Airmail never sees your Microsoft password, it only receives an access token from Microsoft.

If this consent dialog reappears at every launch, the token is not being renewed, and you should re-authenticate the account as described below.

Step 1: Update Airmail and restart it

Make sure you are running the latest version from the Mac App Store or the App Store, then fully quit Airmail (on macOS, use Airmail then Quit Airmail, not just the red close button) and reopen it. A stale sign-in session is often renewed on a clean restart.

Step 2: Re-authenticate the account

On macOS:

Go to Airmail, then Settings (or Preferences), then Accounts.
Double-click the Microsoft account.
Choose the option to sign in or re-authenticate the account.
Complete the Microsoft sign-in page and accept the consent dialog.

On iOS and iPadOS:

Open Settings inside Airmail, then Accounts.
Tap the Microsoft account.
Tap the option to sign in again and complete the Microsoft sign-in page.

A blank Microsoft window means the sign-in page could not be loaded on that device. Try, in this order:

Check your internet connection, and disconnect any VPN, proxy or content-blocking software while you add the account.
Verify the date, time and time zone of your device are set automatically. An incorrect clock is a very common cause of a sign-in page that will not render.
Remove the account from Airmail and add it again from scratch, choosing Outlook or Microsoft 365 as the account type.
Try adding the account on a different network, for example a mobile hotspot instead of a corporate network. Some corporate networks block the sign-in page.

Step 4: If you have a work or school account

Microsoft 365 work and school accounts can be governed by your organisation. If your administrator has not authorised Airmail, the sign-in may fail or ask for approval repeatedly. In that case your IT administrator needs to approve Airmail for your tenant. Please contact your internal IT team, as we cannot grant that approval on your behalf.

About duplicated messages

If messages appeared duplicated after a failed sign-in, they are normally cleared once the account is re-authenticated and the folders resynchronise. Give the app a few minutes to complete the sync after signing in again.

Still not working?

the version of Airmail,
the version of macOS, iOS or iPadOS,
the type of Microsoft account (personal Outlook.com, or work or school Microsoft 365),
what exactly you see on screen.

We will be glad to look into it with you.

Updated on: 07/13/2026

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