hello, I currently have 6 sitemap files 5 of which contain 40000 links each and are less than 10MB in size. their urls are saved in a sitemap_index.xml file. all of them validate ok. however, google has recently started to report errors on them. all the errors reported are: Invalid date An invalid date was found. Please fix the date or formatting before resubmitting. Parent tag: url Tag: lastmod Value: Date found: Aug 3, 2007 Code (markup): I checked the line numbers manually and there's nothing wrong with the lastmod tag and the date format. all the URLs have the same date. anyone has any idea? thanks
i get the same error with my vbulletin sitemaps. i have solved that problem with submitting my sitemaps one by one