Office365 and Legacy Authentication

If you are getting an error such as "The sign-in name or password does not match one in the Microsoft account system", and you have checked the basic account details, your site in Office 365 may be blocking Legacy authentication.

Refer to Microsoft's documentation on conditional policies.

https://docs.microsoft.com/en-au/azure/active-directory/conditional-access/howto-conditional-access-policy-block-legacy

https://docs.microsoft.com/en-au/azure/active-directory/conditional-access/troubleshoot-conditional-access-what-if

To change the settings:

1. Log on to the Office 365 account as a user with Admin Rights

2. In the Admin Settings, navigate to Azure Active Directory > Security

3. View Conditional Access

4. If you have any policy relating to "legacy authentication", exclude the users and groups that need to use the SharePoint integration.

5. Refresh the tray after updating the policy.