We are going to finally switch off the deprecated domain rest.wikimedia.org by September 1st. This should not affect any REST API users, as this domain has been officially deprecated since January & sunset since April [1]. Since then, requests to that domain have returned an error informing users about the move.
Access to the REST API is exclusively through the main project domains, following the following pattern:
https://en.wikipedia.org/api/rest_v1/?doc
Thank you for your cooperation,
mediawiki-api@lists.wikimedia.org