do not get into mail page

do not get into mail page

Hi, 
I do not get into mail page
I log in, insert login, password, then go to  
https://home.zoho.com/home  
and hang in this, do not load page, do not get mail. Nothing.

I tried different brousers and different computers in office, but all the same, I do not get my mail. Problem only from office (IP 81.17.147.142), I have no problem to get into my mail from my home computers.
Our mail domain ovtr.net
Our IP 81.17.147.142

Thanks for help