Cannot send - receive email between zoho/custom domain

Cannot send - receive email between zoho/custom domain

It has been many hours since I setup zoho / domain / mx records (validation ok).

I can send and receive emails from outside zoho/geoerga.gr (e.g. hostgator, yahoo etc), but I cannot receive emails between 2 accounts @geoerga.gr... message says it was sent, but never appears in recipient mailbox @geoerga.gr....

I even tried twice... deleted domain/organisation/closed account and created new account.... still same problem...

http://intodns.com/geoerga.gr
http://mxtoolbox.com/SuperTool.aspx?action=mx%3ageoerga.gr&run=toolpage


Please let me know why this is happening.

POP3/SMTP is working ok (have not received complaints from customer). SMTP also works as I tested the web form.