On free hosting, if you see the message 

"Access to this site has been temporarily denied."

or a '503 error' .  

This is due to the site receiving high levels of concurrent traffic. Once the traffic reduces below the limit access will be restored automatically.

If you see this regularly you should consider upgrading to premium hosting (https://ifastnet.com/portal/sharedhosting.php) 

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