5xx – server error

The variations of server error codes are as follows:

• 500 Internal Server Error: This is a general server-side error without other information. Of course, it is not a good idea to just send 500 for any kind of server error. I am pretty sure that good errors and messages could be provided to help you troubleshoot the error.
• 503 Service Unavailable: This is used to indicate a downstream service's dependency failed. It is quite similar to 502.