You may see an error stating Outlook has exceeded the maximum number of allowed sessions. This prevents you from sending or receiving new emails. The error is typically caused by too many active connections to your mailbox from different devices or sessions.
It often occurs when using Outlook on multiple computers or mobile apps simultaneously. This article provides steps to clear these sessions and restore normal access to your account.
Key Takeaways: Resolving the Maximum Sessions Error
- Sign out of Outlook on the web: Ending your active browser sessions can immediately free up connection slots.
- Close Outlook on all other devices: Shutting down the app on extra computers or phones removes their active sessions.
- Account Settings > Security > View my activity: This Microsoft 365 security page lets you review and sign out of all sessions remotely.
Why Outlook Limits Active Sessions
Microsoft 365 and Exchange Server enforce session limits for mailbox stability and security. Each open instance of Outlook creates a connection to the mail server. This includes the desktop app, Outlook on the web in a browser, and the mobile apps.
The limit exists to prevent a single user from consuming excessive server resources. It also helps protect accounts from unauthorized access by limiting concurrent logins. The exact number of allowed sessions varies by your organization’s administrator settings.
You typically hit the limit by leaving Outlook running on multiple computers. Having several browser tabs open to Outlook on the web also counts. Mobile devices staying connected in the background contribute to the total session count.
Steps to Clear Active Sessions and Fix the Error
Follow these steps in order to resolve the session limit error. Start with the quickest method to regain access.
- Close Outlook on all other devices
Physically go to any other computer where Outlook is open. Close the application completely. Do the same for any tablets or phones using the Outlook mobile app. This terminates those sessions. - Sign out of Outlook on the web
On your current computer, open a web browser. Go to outlook.office.com. If you are signed in, click your profile picture or initials in the top-right corner. Select Sign out. Close all browser tabs for Outlook or Office 365. - Use the Microsoft 365 security portal
In your browser, go to account.microsoft.com/security. Sign in with the same credentials for your Outlook account. In the left navigation pane, select View my activity under the “Security” heading. - Review and sign out of sessions
On the activity page, find the section for recent sign-in activity. You will see a list of devices and app sessions. Click Sign out on any session you do not currently need, especially old ones. Confirm the action. - Restart Outlook on your primary device
Close and reopen the Outlook desktop application on the computer you want to use. Wait a minute for it to reconnect. The error should now be cleared, allowing you to work normally.
If You Use an Exchange or Microsoft 365 Work Account
Corporate accounts may have stricter limits. If the above steps do not work, contact your IT help desk. They can reset your session count directly on the Exchange server. They may also increase your session limit if your role requires multiple active connections.
If the Error Keeps Returning
Outlook Mobile App Running in Background
Mobile apps can maintain a persistent connection. On your phone, force close the Outlook app instead of just switching away from it. On iOS, swipe up from the bottom and swipe the app preview away. On Android, open recent apps and swipe Outlook off the screen.
Multiple Profiles in Outlook Desktop
If you have more than one email account set up in Outlook, each may count as a session. Go to File > Account Settings > Manage Profiles. See if multiple profiles exist for the same account. Remove duplicate profiles to reduce your session count.
Add-ins Creating Extra Sessions
Some Outlook add-ins can establish their own server connections. Start Outlook in safe mode by holding Ctrl while clicking its icon. If the error stops in safe mode, an add-in is likely the cause. Disable add-ins via File > Options > Add-ins and re-enable them one by one.
Session Management Methods Compared
| Item | Manual Sign-Out on Devices | Microsoft 365 Security Portal | IT Administrator Reset |
|---|---|---|---|
| Primary Action | Close app or sign out locally | Remotely end sessions via web | Admin clears all sessions on server |
| Speed | Fast if you have device access | Immediate, from any location | Depends on IT response time |
| Scope | Only the devices you control | All sessions for your account | All sessions for your account |
| Best For | Personal devices you can touch | When away from other devices | Corporate accounts when self-help fails |
You can now clear the maximum sessions error by ending connections on other devices. Use the Microsoft 365 security portal for the most complete remote control. For a persistent issue, check your Outlook add-ins in safe mode. Consider setting a reminder to fully close Outlook on secondary computers when your workday ends.