Can't access mail function after logging in

Can't access mail function after logging in

I've tried this from both iPad and Mac-pro, in Safari, Chrome, and Dolphin. Frequently, after I log in correctly/successfully, when I click on the red "Access Zoho mail" button, the page just re-loads. Repeatedly. It seems totally random as to whether I will be able to access my email on any given day. What is causing this and how do we fix it?