I have tried Chrome and it works and also currently Firefox Beta works but stable Firefox does not. I do not see any point in trying the APP as these other browsers work. I am not sure the Firefox Beta will continue to work though given the current state of the stable version.
I have checked the Discourse current statements on mobile browsers and it says only Safari for IOS and Chrome for Android are supported. This is a very restricted set of browser for a product to support.
By the way the suggestion to try the Discourse hub was worded in such a way as to infer I should use that if it worked. If that was not the intent then perhaps it should have been worded differently to suggest eliminating a device issue. Highly unlikely in my experience for a device to cause this kind of specific issue with a browser.
Stuart