It was probably down at that time. Now it's up and running, but sometime (especially when you don't use IE browser) it is showing error about the link submission process. Their what? They are present, up and runninig now. You could submit directly by DOCS Submit link., but for a more faster, reliable sending, try to register at Microsoft Live (it's different from Hotmail!) and visit the webmater section of Bing. Every SE has his own algorithm. Be patient, your site will be indexed Best answer by now. DO NOT forget to upload the verification XML file from Bing!
you can also submit your sitemap to bing using the following string: bing.com/webmaster/ping.aspx?siteMap=http://www.yoursite.com/sitemap/sitemap.xml Sincerely, Patrick | accomplished technologies llc | accomtec.com
I believe if your site is indexed by Google, sooner or later Bing will also pick it up as well. I didn't submit my site to Bing but it was in there anyway.