Cannot View Free/Busy information of user after Outlook 2016 client upgrade

Scenario:  After a Outlook client upgrade to 2016, you notice that you cannot view/alter the calendar of someone you have delegated permissions for in the Outlook client. OWA works fine and you can still view/alter the calendar through a Outlook 2013 client.

Resolution:  We found that the WindowsEmailAddress is:

• Different than the PrimarySMTPAddress
• not a email alias for the mailbox (The WindowsEmailAddress shows a alias that is not in the proxy addresses/Emailaddresses).

Change the WindowsEmailAddress to an address that matches the PrimarySMTPAddress (which is a alias/proxyaddress for the mailbox)

Set-Mailbox jdoe1 -windowsemailaddress <whatever the primarysmtpaddress is>