I have a user that purchased an Excel 2016 Add-in from the Office Store/App Source thinking he could install it on Office/Excel 2013. The purchase was successful but he could not not install and load it in the Excel 2013 client. That makes sense. But...
After, he upgraded/installed Office 2016 and then when he inserts the add-in the Task Pane opens but he gets the message:
"can’t load this add-in because we couldn’t connect to the catalog"
The OS is Windows 10 and the issue occurs in both the Excel 2016 client and in Excel Online in Chromse and Edge (and I think IE). Tried clearing browser cache etc and also tried the "Clear" button underFile-> Options -> Trust Center -> Trusted Add-in Catalogs.
I think the add-in is in a invalid state because he can install and load other add-ins in the Task Pane that are both for trial and purchase without a problem. Also, I verified that the add-in was in the user's purchased list in his Microsoft Account profile.
Any ideas would be great, including how to get the add-in out of this state because he did purchase it and now it can't even load.