Not quite sure, but it might be because CSP in Safari has gotten much more strict. Also Ionic 2 still doesn’t support iOS 10 officially. For more information check out the following issue (also take a look at the linked topic):
Ok, great, I’m glad that it solved your problem. However I would say that it’s more a workaround rather than a real solution. Therefore I would recommend you to subscribe/vote for the issue and fix your code once a real solution is available.