Problem with Google Sitemaps Verify feature?

Google fails to verify site with message "Our system is currently busy"

[chap0209]

Two days ago, I have submitted a sitemap file to Google Sitemaps.
I have generated the XML file with GSiteCrawler and checked its syntax with a validation tool from smart-it-consulting. So I am pretty sure the syntax is correct.
When the sitemap file became "OK", I created and uploaded on the root folder the empty file Google Sitemaps asked me to create so that it could verify I am the site owner.

Now since that time, all my attempts to verify the site, clicking on the "Check Status" button resulted in message "Our system is currently busy. Please try again in a few minutes."

I would like to know is some of you have succeeded to verify a site for 2 days. Is it a general problem or is it me (though I cannot start to see an explanation)?