Signing in a secured app using a third party email service account

Hello friends, as one of the final steps before deploying my first apps for a company i have been tasked with adding their work emails to the apps users list, so that they don’t have to use their personal mails (it’s against their policy).

The service provider in this case is cPanel, i’ve tried logging in to all the listed authentication providers to no avail, is there any way i can make this work?