Cannot open emails or receive / send

Hi all,

I signed up yesterday with Zoho and my domain. One day later I cannot receive or send emails and I am getting the following error:

Problem in sending email while doing IO operation

My inbox does not show any new messages nor does it allow me to open the messages that are there.

Is this another glitch with Zoho? I read quite a few entries with this same issue and the result seems to be always a glitch at the server end.

Help please! I have important work stuff to reply to and my confidence has been eroded with this experience.