In Office 365 two factor authentication (2FA), App Password is used for older versions of Microsoft Outlook or for non-outlook clients on devices like MACs or smart phones.
After enforcing 2FA in Office 365 and if you are trying to configure Outlook 2016 for email, and Outlook keeps rejecting the password that you have been using and that works with OWA, while if you try the App Password it works in Outlook, then you might want to add a registry key to enable and enforce Modern Authentication.
- Outlook 2010 doesn’t support Modern Authentication
- Outlook 2013 supports Modern Authentication but you need to add the following two registry keys. DWORD and set to i
The following key will enforce it.
- Outlook 2016 supports modern authentication and it is ON by default but we’ve had to enforce it in some instances because Outlook kept prompting for a password and wouldn’t take the password that worked with OWA but Outlook worked with App Password. Enforcing Modern Authentication made Outlook 2016 accept the regular office 365 password (that worked OWA password). Add the following DWORD and set to 1
Note: registry changes might result in problems and serious issues with computers and software. Do it at your own risk.