I submitted simple text sitemaps for subdomains 2 weeks ago. All have been assigned a status of "OK", but when I look at the crawl stats of pages under these subdomains, it lists the URLs on my sitemaps as "unreachable URLs", with "5xx error" indications. The "last calculated" dates of the crawls vary, and there's no way my site has been down this frequently. I click the URL links that are listed on the crawl stats and they all work. Any ideas?