Recently, google webmasters has announced that the Url inspection tool of Google Webmasters have disabled due to make some infrastructure changes. Now request indexing feature of Google Search Console is not available for some upcoming days.
The above information was tweeted on twitter official account of Google Webmasters. They has also intimated that the Url inspection tool will be back available as soon as possible in upcoming days.
The page indexing of webpages will continue as per regular method during these maintainance days. After infrastructure work will complete, you will be able to request indexing again in Google Search Console.