Prototype link not working during usability test

I'm having issues with my prototype link specifically during a usability test. We're testing mobile prototypes and when I test these on my personal device everything works great. No issues what-so-ever. However, when the links are shared during the usability test (which has screen sharing among other things all happening at the same time), the prototype won't load at all. 

Could there be issue on my end that is causing things to not function properly when sharing the link?