Webmaster tools robots.txt errors. How long before solved at webmaster tools?

Hi everyone, I just moved my wordpress site to a new host last week, I got a error message at webmaster tools during that time that google bot couldn't access my robots.txt, problaby because we suffered a couple of hours of downtime. After the migration I fetched robots.txt it as google and it says success but the error message "Google couldn't crawl your site because we weren't able to access robots.txt" keeps staying there.

This week it the warning changed to a yellow exclamation point. Anyone have any experience in getting this error message to go away? After the date of the errors there are no red dots or blue dots that says failed attempts on my webmaster tool graph.

I should mention that the only thing at my robots.txt currently is

#Begin Attracta SEO Tools Sitemap. Do not remove
sitemap: cdn.attracta.com/sitemap/url.xml.gz
#End Attracta SEO Tools Sitemap. Do not remove

Anyone with any experience with this kind of issues? Is there something wrong with my robots.txt? How long does it usually take for webmaster tools to show that the issue have been solved?

I have attached the graph from my webmaster tool. Any insight would be much appreciated.