Access to this site has been temporarily denied.

On free hosting, if you see the message 

"Access to this site has been temporarily denied.
This is due to the site receiving high levels of concurrent traffic.
Once the traffic reduces below the limit access will be restored.
If you are the webmaster and are seeing this often you should consider upgrading at SecureSignup.net"

This means your site has exceeded the number of http connections per second allowed for a free hosted site.  

Once the number of connections per second to your site goes below the threshold access will be re-allowed.

If you see this regularly you should consider upgrading to premium hosting (https://securesignup/net/portal)

Or click the UPGRADE ACCOUNT button in your free hosting cPanel, when you upgrade using this link all your existing files/domains/databases are automatically upgraded to premium !