HansPrive on "[Plugin: WordPress SEO by Yoast] Fetch as Bingbot result: "unexpected error""

When I use Bing Webmaster Tool "Fetch as Bingbot" for my homepage the result is: "unexpected error".
I just recently started using WordPress-SEO.

Questions:
Where should I look and what should I do?

http://wordpress.org/extend/plugins/wordpress-seo/