In the console:

{
    "status": 400,
    "errorCode": "subscriptionNotAvailable",
    "data": {
        "message": "Realtime subscription is unavailable at this time."
    }

Hi Melissa, 

Welcome to Box Community and glad to assist! 

The Box Embed Widget is not optimized for mobile browsers.  You should not use it in Web experiences designed for mobile devices.

To know more about Box Embed Widget, please see this article. 

Thanks for posting!