When your website is not working or certain pages are unavailable, you may encounter various types of error messages. Error codes display a certain number and their type can be determined based on the first digit: 1xx: Informational, 2xx: Success, 3xx: Redirection, 4xx: Client Error, 5xx: Server Error.

Client (400-499) and server errors (500-599) are quite common and when dealing with them, be sure to refresh the page in your browser after making changes on the server  and check server logs for more details if the issue persists.

DigitalOcean has provided a list of common client and server type errors, what causes them and detailed explanations how each one can be resolved.

Error Server Digital evidence Site