This application cannot be used because it is not allowed by your Box administrator.

Hi there, 

Welcome to the Box Community, I'm happy to help!

Please be advised that the Box Integration with Office desktop applications is only available for computers running Windows, and currently not available to Mac devices.

To learn more about Box for Office integrations, please take a look at this article: https://support.box.com/hc/en-us/articles/360044196433-Box-for-Office-Integrations#h_3fecec92-f129-4920-aba3-d6eb54123de6

All the Best,