In mobile view you should have different aspect ratio for the image. Like in instagram. Full HD will fill only half of mobile screen (aprox).

Contact the app developer. If the problem started after you installed the app. 

You have so many errors on the page! And the page loads with working button but it's brakes for some reason: 

From customer point of view, I can't tell much, but here you do have a button (or in this case a input of type Submit) -  You probably are doing something different. Do you have some plugin or extension interacting on the page with problem (something...

Hello, Yakka, There is no button to be clicked in this form: Maybe you missed something!