In this particular case, user was running Office Standard 2016 and I upgraded to Office 365 Business Apps. Upon checking the account, it still showed as Standard. This also affected the Online Archive mailbox in Outlook.
In a nutshell, you have to search for all the license keys on the computer and remove them. Close out all Office apps, open and check again.
Within the appropriate folder (eg c:\program files\microsoft office\office16), run the following script:
cscript ospp.vbs /dstatus
Referencing the last 5 characters of the product key, run the following script (adding the last 5 characters shown above.)
script ospp.vbs /unpkey:
Repeat per license key that you may have. I had 3 but you may only have one.