This is a very basic check, expired domain registration has been the cause of a website being down, so just starting with the most obvious checks first.
Registrar Registration Expiration Date: 17-May-20XX Status: ok
Note .au does NOT display expiry date however the status will look something like this if it's expired Status: serverHold (Expired) Status: serverUpdateProhibited (Expired)
If your domain has expired proceed to step 3
If your domain is ok proceed to Step 4
Step 3 - Domain Expired Contact the company your domain is registered with, if it's Netracom then you have 30 days to pay invoice before the domain becomes unavailble to renew (dependant on domain authority policy at the time)
If your having trouble please contact our support@netracom.net we will be able to track the company or provider who your domain is registered with.
Step 4 - Blocked Access Now that we have confirmed your site is online but not you, it appears that your IP has been blocked by our server's firewall. 5 successive unsuccessful login attempts to your cpanel, your WHM, an FTP account or an email account, can trigger the firewall to block that connecting IP, as the server treats that IP as a possible intrusion threat.