I am trying to activate one of our users Office 2016 on an Apple computer. I have made google chrome the default browser. I have the OKTA plugin installed in google chrome and safari (both of the browser the user has installed). I have gone through OKTA and gone to our Office 365 Portal and downloaded Office 2016. The programs are installed and I am trying to activate them now. I launch Outlook and am prompted to input the users email addresss. After inputting the users email address it redirects us to the OKTA login page in a smaller window. (I do not know which browser this is using, but it does not appear to be the default browser or safari). The user logs in with ther OKTA credentials and is then presented with the default OKTA login page saying that the OKTA browser plugin is required for some of your applications and the OKTA browser plugin is not availible for your browser. (Normally this would just activate at this point and you would never see this page). How do I get Office 2016 to activate in this situation?
It looks like either the Microsoft side or the OKTA side is trying to use Secure Web Authentication (SWA), or Form Based Authentication. This is the only reason the OKTA would pop up and ask for a browswer extension. It seems pretty clear to me that federation is setup on the Microsoft side just fine, as O365 is directing you to the proper SSO server and is using WS-Federation. If you are familiar with PowerShell I would just look up the MS Technet article on O365 federation and make sure it is setup correctly, and then make sure the OKTA application is setup correctly.
I am using a Mac with O365 and had no problem activating Office 2016 desktop apps with OKTA.