Problem with digital Edition in my mobile phone (not a zoom option in my screen)

Hi, yesterday from play store downloaded the digital edition and I authorized it with my e-mail

I downloaded also a purchased book without any problem (from BPP university) and I see all the book.

When I open the book I cannot increase the pages with my fingers (zoom) and there are very small letters, also the same problem is also with book "Getting started with Adobe Digital edition".

All the other free articles I can increase the screen with my fingers and there is not any problem.

Only with Adobe Digital edition in my mobile phone I have this problem. In my PC I correct this with tab change page view and select Zoom 1,5 x.

My phone uses Android 7 and it is a Huawei P9 lite.

Can someone to help me?

Thank you in advance

Kostas Palaskas