First, if your website is coming up as unavailable, it may or may not actually be down. Our servers are monitored every 5 minutes and if a site is down we will know about it right away and start work on getting it back up as fast as possible.
Most of the time though someone on your network has attempted to log into the server with a wrong username or password and the server has blocked your Internet connection. You can try this by looking at your website from a computer at another location like work or home. Please submit a support request from the computer having issues and we will work to resolve it ASAP!