OnePlaceMail App for Outlook
Unable to sign in when using OnePlaceMail for Outlook App.
The OnePlaceMail for Outlook App currently has the following account requirements:
The following environments are not supported
There is a known issue with ADFS and Desktop Outlook 2013 (this relates to IE11 which is used by Outlook 2013). To confirm this is your issue, you should be able to sign-in and use the app using Outlook Web Access in a Chrome or Firefox web browser.