Update: This is no longer an issue.
If you are having problems connecting to public folders with your InfoQuest Hosted Exchange service
please contact support.
If you recently upgraded to Outlook 2016 and are on Hosted Exchange and you had access to Public Folders, there is a bug with Outlook 2016 that Microsoft is aware of and coming out with a fix soon.
If you need to access your Public folders, you'll need to use Outlook 2013 until the fix is pushed out from Microsoft.