ZOHO Mobile Friendly Template too small and left justified.

I used a mobile friendly template to create a email campaign using ZOHO Campaigns. The test email revealed the received message was under-sized and left justified. When I turn my iphone to landscape view, the template fills the screen. When I turn it back to portrait view, sometimes it stays full size and other times it shrinks again. (see attached picture for shrinked view).

What needs to be done so the email is full size on a smartphone when it is first opened???