I implemented the unavailable_after tag in my pages like the below and set to unavailable after 3 days but in Google Webmaster Tools I got 404 for that page.
<META NAME="GOOGLEBOT" CONTENT="unavailable_after: 05-May-2014 15:00:00 EST">
How do I know Googlebot visit(crawl) my pages again to read this tag (or) how long Googlebot will take to crawl the pages again ? please give me a suggestion!.
Note: I set unavailable_after tag for certain content types(not whole website) with highest priority(1.0) in XML sitemap.