Google is ending support for sitemap ping and the endpoint will stop working by the end of this year. Google has announced that it is announcing a "disabling of the sitemap ping endpoint." This means that HTTP ping requests will result in a 404 error.

Google said the Web Protocol defines an unauthenticated REST method for submitting sitemaps to search engines. This is a way to "ping" or tell search engines that the sitemap has been updated.