Problem with sent e-mail with IOS

Problem with sent e-mail with IOS

Hi, 

I am a brazilian guy, so the printscreen problem is portugues, but I will explain the problem ....

I have a Iphone 5s and a few days ago the zoho e-mail was working perfectly, but today I can´t sent e-mails with my smartphone.

I need sent some e-mails today with my iphone yet, but I can´t because the problem bloque. 

Please, Can someone fix this problem to me ?

Thanks