Workaround for: Outlook 2016 Adding an Exchange Account: Log onto Exchange ActiveSync mail server fails

Outlook on Windows 10 does not work very well with ActiveSync, for better performance set up the Zimbra connector for Outlook (Windows).
This feature is only available on our Pro-level mailboxes.

Symptom:
With Office 365 - Outlook 2016 - Microsoft do not allow custom settings in outlook 2016 setup, and you are seeing this error after setting up an account in Outlook mail 2016

Something went wrong
or
Log onto Exchange ActiveSync mail server (EAS): The server cannot be found.

Solution:
Close Outlook and re-open it.
Click on menu Files->Account Settings->Manage Profiles
Allow Microsoft Outlook to make changes.
A new Mail Setup Window will Open:

• Click on Email Next to "Set up email accounts and directories".
• Click on New.
• Click on "Manual Setup or Additional Server Types", then Next
• Select "Exchange Active Sync", then Next

Then enter:

• Your Name: Your real name for this account
• Email Address: Your full email address
• Mail server: the HIS server name: mail.his.com, zmail.his.com, zimbraxx.his.com...
• Username: Your full email address
• Password: Your email account password.
• Check the checkbox next to "Remember password".
• Choose the Mail to keep Offline. Default is All, shorten to 1 month if you want.
• Click Next.
• Wait for it to logon and verify
• Click Finish.

That's it.

As an alternative you can also follow Microsoft instructions to Disable Simplified Account Creation in Outlook 2016