503 Service Unavailable
Published in Networking.
The 503 status code, or Service Unavailable error, means that the server is overloaded or under maintenance. This error implies that the service should become available at some point.
If the server is not under maintenance, this can indicate that the server does not have enough CPU or memory resources to handle all of the incoming requests, or that the web server needs to be configured to allow more users, threads, or processes.