Solved

How to repair the app not loading dialogs ("popup windows")

I have just uploaded some code that may help. Please try once again to clear data and reload the application if you can.

UPDATE: Reports are coming in that the latest fix is working.

It seems to me that the issue is iOS 10 and Android 4.4. The reason for this is they use a different browser engine to later versions of Android and iOS. So whatever the issue is, we've tracked it down now to specific browser engine versions. We're getting warmer...

Regarding the couple of Android 6 reports we've had, I suspect those may be resolved if we can resolve the issue on Android 4.4 and iOS 10.

That's correct. I will get technical / nerdy here, but let me explain how this works:
Essentially the "Internet" app is an old version of the WebKit engine, and it is no longer used or supported by Google. However, it is what runs on old versions of Android (like 4.4 KitKat) and older iOS versions used it too. When a website is placed inside an app this is called a "WebView" and this is where the issues are arising. Different OS platforms use different versions / engines for rendering these WebViews. Depending on your version of Android, it may use the engine from your "Internet" app to render the pages inside iGP Manager. Are you on Android 4.4 or lower?

Have you tried clearing the cache as instructed in the first post in this thread? I have just uploaded code that means you need to do this again potentially as of about 10 minutes ago. New code / a fix was only just uploaded in response to all the feedback and information we got.

It's such a relief to see it working for you all. Thank you so much for your patience and persistence under difficult circumstances. I appreciate this has obviously been frustrating for everyone. Phew! That was a complicated one to debug.

If anyone needs further support for any inconvenience caused while this was happening please email support@igpgames.com.