When sending a test message, please be sure it is plain text and seems like a 'real' email message. It's important to make sure the message is not being blocked on the outgoing end, and otherwise normal things like PDFs and Excel files can end up activating spam filters.
If other accounts using the same domain are receiving mail but this one account is not, it's possible you have a mail client connected with POP that you forgot about. POP connected clients will, by default, download everything the email receives and delete the copy on the server side. When you try to connect to the email account from other mail clients, or by logging in to webmail, it will appear that the email is empty.
The other time I have seen something like this is when a custom email forwarder was set up on a VPS account that sent the email elsewhere before it reached the original address.
If neither of those turn out to be the case, I would suggest analyzing the mail logs or checking with our 24/7 Technical Support team for further help investigating the issue.
Customer support service by UserEcho