I am trying to force the Duo prompt for O365 (outlook mostly) each time a user accesses via a browser, or from their mobile device app.
I have an application policy set to “dont remember devices”, but my android phone just logs me in still.
I originally clicked remember this browser in my outlook app on my phone.
Whether Azure/365 requires a user to perform Duo authentication again is up to Azure/365 and its token set on the client device during authentication.
This Duo Knowledge Base article should get you started with understanding what you might need to change in Azure/365: How often will rich and mobile clients such as Outlook, Skype for Business and iOS Mail prompt for authentication with Office 365?.