What is the primary cause of a 504 Error Code?

[datarecovee]

Error Code 504 is mainly caused by server overload. This occurs when the server you are connecting to (the backend server) such as an application server or a database server is too slow to respond to traffic (or due to script errors) or simply has limited resources. By waiting until this response is received the gateway server fails and provides the Error Code 504 Gateway Time-Out.