If you’re anything like me, you’ve probably found yourself knee-deep in work emails, trying to conquer your inbox like a hero.
But hold on tight because there’s this one issue with Microsoft Outlook I recently encountered that had me scratching my head and frantically searching for solutions: the dreaded Outlook error codes AADSTS90072 and AADSTS1002016.

You will see the error message,
“Sorry, but we’re having trouble signing you in.
AADSTS90072: User account ‘xxx’ from identity provider ‘xxx’ does not exist in tenant ‘xxx’ and cannot access the application ‘xxx'(Microsoft Office) in that tenant. The account needs to be added as an external user in the tenant first. Sign out and sign in again with a different Azure Active Directory user account.” or
“Something went wrong
Unfortunately we’re having trouble signing you in. Try again in a few minutes. If this doesn’t work, contact your support person and report this error.
AADSTS90072: User account ‘xxx’ from identity provider ‘xxx’ does not exist in tenant ‘xxx’ and cannot access the application ‘xxx'(Microsoft Office) in that tenant. The account needs to be added as an external user in the tenant first. Sign out and sign in again with a different Azure Active Directory user account.”
Trust me, I know the frustration of getting hit by these error messages right when you’re on a roll. So, let’s dive into what these error codes are all about, unravel the mystery behind them, and, most importantly, figure out how to give them a one-way ticket out of our digital lives.
What are Microsoft Outlook Error Code AADSTS90072 or AADSTS1002016

AADSTS90072 and AADSTS1002016 are error codes associated with Microsoft’s Azure Active Directory (Azure AD) authentication service, commonly used for user authentication and access management in various Microsoft services, including Outlook. These error codes indicate issues with user authentication and identity verification.
- Microsoft Outlook Error Code AADSTS90072 – This error code typically indicates a user authentication failure due to a token issue. It occurs when the user’s authentication token is no longer valid, often due to password changes, token expiration, or a session timeout.
- Microsoft Outlook Error Code AADSTS1002016 – This error code is closely related to the AADSTS90072 error. It indicates that the user’s authentication token has expired or is invalid. It often accompanies a message stating, “The user or administrator has not consented to use the application.”
Common Causes of these Microsoft Outlook Error Code AADSTS90072 or AADSTS1002016
- Password Changes – If users change their password, their existing authentication token might become invalid, leading to the AADSTS90072 error.
- Token Expiry – Authentication tokens have a certain lifespan for security reasons. When a token expires, users need to reauthenticate to generate a new token.
- Session Timeout – If a user’s session remains inactive for a certain period, they might need to reauthenticate upon trying to access a resource.
- Consent Issues – The AADSTS1002016 error often occurs when an application requires user consent to access certain resources or perform specific actions, but that consent hasn’t been granted.
Ways to Resolve the Microsoft Outlook Error Code AADSTS90072 or AADSTS1002016

Re-authenticate your MS Outlook Account
If you encounter either of these errors, the first step is to try reauthenticating. Log out of your Outlook account, close the application, and log back in.
Clear Browser Cache and Cookies
Sometimes, cached data can interfere with authentication. Clear your browser’s cache and cookies, and try logging in again.
Update Application Permissions on Microsoft Outlook
If the error message mentions consent issues, the application might need certain permissions to access your Outlook account. Check the application settings and grant the necessary permissions.
Check Time and Date Settings on your Device
Ensure your device’s time and date settings are accurate. Incorrect settings can lead to token validation issues.
Password Reset your MS Outlook Account
If the error persists, consider resetting your password. This should generate a new authentication token.
Contact Microsoft Customer Support
If you’re part of an organization, contact your IT support team for assistance. They can provide more specific guidance based on your organization’s setup.
Preventive Measures to Avoid Microsoft Outlook Error Code AADSTS90072 or AADSTS1002016

To minimize the occurrence of these errors:
- Regularly update passwords.
- Keep your device’s time and date settings accurate.
- Stay logged in or refresh your session if there’s inactivity.
- Consider consent requests when using applications that integrate with your Outlook account.
Remember, technology hiccups happen to the best of us. Still, with some troubleshooting and some tech-savviness, you can get back to conquering your inbox without those pesky error messages slowing you down!