Can you name examples of the 500 series of response codes in protocols or network standards?

Examples of 500 series response codes in various protocols and standards:

• HTTP:

  • 500 Internal Server Error — internal server error
  • 501 Not Implemented — method not implemented
  • 502 Bad Gateway — bad gateway
  • 503 Service Unavailable — service unavailable
  • 504 Gateway Timeout — gateway timeout

• SMTP (email protocol):

  • 500 Syntax error, command unrecognized — syntax error
  • 501 Syntax error in parameters or arguments — parameter error
  • 502 Command not implemented — command not implemented

These codes indicate problems on the server or service side.