Site not Working

System Issues
1

My Both sites are not working they displayed the error

  1. http://parivartechnologies.ezyro.com
  2. http://yogeshsaxena.ezyro.com/
2

The same
http://forumluniksamp.ezyro.com/

3

503 Service Unavailable
Failed to resolve the name of server manualotprefund.ezyro.com