I can Send Emails, but I am not Receiving emails in Zoho Account on app and on webpage

I can Send Emails, but I am not Receiving emails in Zoho Account on app and on webpage

Hi,

I have problem with receiving emails.
I can send emails, but I am not receiving emails in Zoho Account on app and on webpage.

That stop 3 days ago. 

It show error "host not reachable"