So the auto-configure for your Outlook account should take care of your initial setup but obviously there's something that's hanging up the process.
This is just speculation but just for posterity, re-install the Outlook app. Don't start it up, just re-install it. Now go into your phone's Settings >> Application manager, find the Outlook app, and tap on the 'Clear data' button. Now tap on the 'Uninstall' button. (Just uninstalling the app doesn't necessarily clear all its configuration settings.) Restart your S6 so everything gets reset and then try going the same process you did before to set up your Outlook account into your phone. Hopefully you'll just need to enter your email address and then password with the auto-configuration doing the rest this time.
https://support.office.com/en-us/ar...5-b835-f8e532091872#OutlookforAndroid=_STEP_1
If it's still hanging up on that 'Checking incoming server settings...' message, here's a link with the manual settings:
https://www.outlook-apps.com/outlook-com-pop-settings/
Regarding the default Android email app, all I can say about it is while it is good for the most basic email needs, it's lacking for anything more than that. Third-party email apps generally provide a lot more functionality and often stability. As you didn't find the MS Outlook app to be your preference I'm going to tentatively suggest you give the Blue Mail app a try, if only because it has good Outlook interaction built into it:
https://play.google.com/store/apps/details?id=me.bluemail.mail&hl=en
Pair up your S6 with your Outlook account, skip trying to set up the default email app, and use the Blue Mail app. If you don't like it either, go through the 'Force stop', 'Clear data', 'Uninstall' process to remove it, and use the default Android email app.