Blank Screen Windows Phone

I’ve written an Ionic test app, it has been deployed to azure as a web app for test purposes (no cordova stuff yet).

I can successfully view the app in all desktop browsers (Edge/Chrome), but when I navigate to the site using Windows Phone 8.1 I am met with a blank screen, no errors popping up or any indication of failure, just a blank screen.

What might be the cause of this?

Update: this is also happening when I browse to the site on an iPhone, iOS 7

Thanks,

Slicc