I just re-submitted my sitemaps to Google Webmaster Tools and a big red cross is appearing as the status next to both sitemaps. Why has this suddenly happened? They still exist on the site. The only change to them is that they have been updated. Could someone please help? Thanks in advance
hard to say why as there could be various reasons. check the coding of the sitemap and make sure the sitemap url is right
If you click on the sitemap name it should take you to a page that will explain what is casing the errors.
I sorted it all now. It was because I set up a subdomain and for some reason it conflicted with the sitemaps on my main domain. Oh well, all sorted now!