Outlook 2013 not accepting Microsoft 365 password
Microsoft has recently made changes to the Office 365 Exchange email servers to improve overall security. These changes have caused connection issues with users that are still utilizing the older Outlook 2013 email client to access their email. Users using Outlook 2013 will be prompted to reenter their password to connect with the Microsoft 365 Exchange server. Upon entering this password, Outlook will then prompt for the credentials again. Acting as if the password for the account had been entered incorrectly.
Outlook 2013 doesn't have modern authentication enabled by default. Which is causing the condition in Outlook 2013 where the password is not accepted and the software prompts for the credentials in a loop. Even though the correct password has been entered each time. This is due to Outlook 2013 forwarding these credentials to the Microsoft 365 Exchange server in a method that's no longer supported.
Solution 1: Apply the registry fix to enable modern authentication in Outlook 2013
Since the issue is a result of Outlook 2013 not supporting the modern authentication methods by default, we have the option to enable these modern authentication methods via use of the Windows Registry. This can be performed by first closing Outlook and then copying and pasting the following three commands into a Windows command prompt running with administrative privileges.
REG ADD "HKCU\Software\Microsoft\Exchange" /v AlwaysUseMSOAuthForAutoDiscover /t REG_DWORD /d 1 /f
REG ADD "HKCU\Software\Microsoft\Office\15.0\Common\Identity" /v EnableADAL /t REG_DWORD /d 1 /f
REG ADD "HKCU\Software\Microsoft\Office\15.0\Common\Identity" /v Version /t REG_DWORD /d 1 /f
Launch Outlook after these commands have been ran successfully. You'll be prompted to enter your Microsoft 365 account password. This time in a more modernized login prompt. After entering the correct password in this window, Outlook will finish loading and successfully make the connection with the Microsoft 365 Exchange server. Apply this fix under each Windows user profile that makes use of Outlook 2013 to connect with Microsoft 365.
Solution 2: Upgrade Microsoft Office to a supported version
The registry fix outlined within Solution 1 may become obsolete at some point in the future. It's best practice to upgrade to a supported version of Microsoft Office to prevent any further service interruptions and continually maintain a supported version to stay up to date and secure.
At the time of writing, Microsoft 365 services support the following Office versions:
- Office 2016
- Office 2019
- Office 2021
- Microsoft 365 Apps
The link below will provide further details on the supported Office versions:
https://learn.microsoft.com/en-us/deployoffice/endofsupport/microsoft-365-services-connectivity