It appears Microsoft have now removed support for Exchange 2007 within Office 2016/Outlook 2016.
Traditionally Microsoft only support the latest three versions of Exchange which for Outlook 2016 are:
Anything other than this will not work, and you will get the following message:
“The resource that you are trying to use is located on an unsupported version of Microsoft Exchange. Contact your e-mail administrator for assistance.”
We recommend downgrading to Office 2013 for Exchange 2007.