A family of Microsoft word processing software products for creating web, email, and print documents.
I had the same exact error. Microsoft support from another country helped me. You need to have Internet Explorer installed your your computer. I had mine uninstalled. You can restore it through Control Panel -> Programs -> Programs and Features -> Turn Windows Features on and off -> tick Internet Explorer 11 -> restart your computer.
Add-ins work perfectly in my office 2016 after I did it.