A checklist of things to check when your website / game / service is down.
1. Check your backend
Ping your backend IP.
Check the error log (On the services page, Action > Error Log)
Login and check that everything required to run your service is running (nginx / apache2 / mysql etc)
Try connecting directly to your backend and confirm everything is working
Disable your firewall and see if that helps. If this helps see Adding a firewall exception
2. Check the node status
It does happen occasionally that things go wrong, either on our end or on our providers networks.
You can check the status of any server on the Server Status page.
3. Check connectivity from your location
Use a service like just-ping and perform a world wide ping. Also of interest is isitup for testing HTTP ports.
4. Open a support ticket
We will do our best to help, just be patient.
If your domain is correctly setup using our fallback service then your site should be served by a temporary IP within a few minutes.