# 4nn Client errors

## 400 Bad request

The HTTP code 400 indicates that the server could not understand the request due to incorrect syntax.
The client should NOT repeat the request without modifications.

For more information see [https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Status/501](https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Status/400)

## 401 Unauthorized

The HTTP code 401 indicates that the request requires user authentication information.
The client MAY repeat the request with a suitable Authorization header field

For more information see [https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Status/501](https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Status/401)

## 403 Forbidden

The HTTP code 403 indicates that the client does not have access rights to the content.
Unlike 401, the client’s identity is known to the server.

For more information see [https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Status/501](https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Status/403)

## 404 Not Found

The HTTP code 404 indicates that the server can not find the requested resource.

For more information see [https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Status/501](https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Status/404)

## 405 Method Not Allowed

The HTTP code 405 indicates that the server could not understand the request due to incorrect syntax.
The client should NOT repeat the request without modifications.

For more information see [https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Status/501](https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Status/405)