PDFMOfficeAddin wouldn't install into Outlook 365

I have went to com add-in, browsed to the directory and select the PDFMOfficeAddin.dll file.  Nothing happens and it doesn't get added to the list.  I was using Adobe XI, so i thought I would try to upgrade and purchased Adobe DC.  I un-installed XI before installing DC.  Still won't load the PDFMOfficeAddin.dll file. 

I was exporting Outlook folders to PDF files and then this option disappeared? 

I am running Office 365 ProPlus version 16.0.6741.2071.