I am trying to create an annotation in a YouTube video to link to a blog post. The URL I am trying to link to is http://laggacy.wordpress.com/2013/03/15/slender-the-arrival-beta-preview-extra-content/ but when I try to enter that into the field I get an error saying Please enter a valid URL.
I have verified my channel, I am part of YouTube's (new) partnership program, I have associated the website and I have enabled my account for external annotations. Why won't this work? Is it because I'm hosting the blog on a subdomain?