Can not use my Sharepoint APP on my iPhone

I hope somebody can help me, but I have had very bad experiences in Microsoft Forums.

I'm deploying all the collaborative platforms in my organization and I wanted to use the Sharepoint APP

on my iPhone.

When I log in the following screen appears, (that it's not the normal screen)

I have to add that if I try to log in on another iPhone the app works perfectly.

Thanks in advance!