Iphone 6 cant read magazines

I downloaded Red magazine on subscription to my iPhone 6, the app and the magazine issue itself opens up, however the pages are tiny! I cant zoom on the articles and theerfroe cant read them as the pages and writing are so small. When i try to zoom, a pop saying you can't do this appears.

Is there some way around this, as I really am starting to feel as though I have wasted my money. Does anyone know a way around this?

Thanks,

Corinne