If your site is offline (you are getting a timeout message or it does not open), you can try a few things.
If the site is up for everyone else, it might be that your IP address was blocked by the Sucuri Firewall or a software firewall on your host. It is very rare for this to happen by mistake, but it can happen. If the Sucuri Firewall blocked it, we will unblock it in 30 minutes. If you need access restored sooner, please open a support ticket and include your current IP address to allow us to troubleshoot the issue.