The server is temporarily overloaded or down for maintenance. Gateway Timeout
A "5xx Server Error" report indicates that a website's server encountered a problem that prevented it from fulfilling a user's or a crawler's request . Unlike 4xx errors, which usually mean a user made a mistake, 5xx errors mean the is at fault. Common 5xx Error Types Status Code Likely Cause 500 Internal Server Error 5xx Server Error
The site has used up its allocated data transfer for the period. Why This Matters (Impact) The server is temporarily overloaded or down for maintenance
One server received an invalid response from another server it was trying to talk to. Service Unavailable 5xx Server Error