There could be many reasons why.
We'll try a few things it could be.
Have you got blocked by the server? Incorrect password for cPanel,
protected directory, sending or receiving emails?
A quick way you can often find this out is if you try view your site a
message should be displayed similar to this:
Your connection to this server has been blocked in this server's firewall.
You need to contact the server owner for further information.
Your blocked IP address is xxx.xxx.xxx.xxx
This server's hostname is xxxxxx.xxxx.xx
If you do infact see the message you will need to contact us and provide us
with the IP that has been blocked. We will be able to quickly unblock
the IP and let you know why it was blocked so it won't happen again.
Do you see a suspended message when you view your site?
There are many reasons why your site may have been suspended, most commonly
an invoice is unpaid (check your spam folders just in case). Sometimes it can be due to a hacker gaining access to your site, in that
case we need to suspend your site to protect any further damage to your
site, and the server. We always email the account holders email
address when we suspend a site for any reason.
I have uploaded my site but I just do not see it. Did you upload your site to the public_html folder/directory? If not you need to place your files inside that folder/directory. Make sure your 'home' page is called index.html, index.htm and index.php will also work