Many huge sites lose their pages in the Google index for misusing 403 status codes while should be used with 503s.
We’ve seen huge sites lose loads of their pages from our index because they were serving them with a 403 status code instead of a 503.
A 403 means a forbidden code and this status code used to remove content from the Google index.
The server understood the request, but is refusing to fulfill it. Authorization will not help and the request SHOULD NOT be repeated. If the request method was not HEAD and the server wishes to make public why the request has not been fulfilled, it SHOULD describe the reason for the refusal in the entity. If the server does not wish to make this information available to the client, the status code 404 (Not found) can be used instead.
A 503 is a temporary Service Unavailable code and does not stand for quick content removal from the search engine index.
The server is currently unable to handle the request due to a temporary overloading or maintenance of the server. The implication is that this is a temporary condition which will be alleviated after some delay. If known, the length of the delay MAY be indicated in a Retry-After header. If no Retry-After is given, the client SHOULD handle the response as it would for a 500 response.
Better to be more conscious while occurring errors which will impact Google traffic.”