Microsoft offers 3 ways that you can use your office 365 Email account in a 3rd party application. You can find the article here. For a reference we’re including the way we found fastest and easiest to be used with QSX and other applications.
Note: If you’ve already been able to send out Emails from another application using your 365’s emails, you should be able to do that with QSX with the same parameters as well and you don’t need to take these steps.
This is a good starting point article from Microsoft. It is not written by us and you may have to Google current answers. In Oct 2018 – a customer had success with option #3 in this article:
Now you are all set. You just need to come back to QSX software, Enter the name you got from Microsoft on step #1 as your SMTP server, and set the port to 25. You may use your Email address in QSX and you DO NOT need to enter any password or authentication.