A graphic design agency has an Office 365 tenant. The agency uses only computers that run the Apple Macintosh operating system.
Some users have Microsoft Entourage 2008 for Mac, and some have Microsoft Outlook for Mac.
All users report that they cannot access Exchange Online to check their email. You need to run test connectivity for all users to identify the problem. You need to
use the Microsoft Remote Connectivity Analyzer and the credentials of the users.
What should you do? To answer, drag the appropriate test to run to the correct email client. Each test may be used once, more than once, or not at all.
You may need to drag the split bar between panes or scroll to view content.
Answer: 
Explanation:
https://testconnectivity.microsoft.com
Entourage 2008 For Mac has a web service update, that uses EWS as communications protocol.
Only the text doesn’t stated the web service is installed.
Other wise it’s IMAP or POP. An SMTP test will not show what is the problem, that the client software cannot connect to Exchange Online.
So that means that the EWS check needs to be preformed. The IMAP\POP3 isn’t an available answer.
Entourage 2008 for MAC: Microsoft EWS
Microsoft Outlook for Mac: Microsoft EWS
Out of Office Assistant: When connecting to an Exchange 2007 CAS, it works thru ‘Exchange Web Services‘
https://blogs.technet.microsoft.com/amir/2008/02/09/how-does-entourage-work/
Microsoft Exchange Web Services Connectivity Tests
Both Outlook 2011 & Outlook 2016 for Mac connect to Exchange via Exchange Web Services (often abbreviated to EWS).