We see occasional reports, in Blogger Help Forum: Get Help with an Issue , from Blogger blog owners who want to share their blogs using BlogLovin. Why can't I claim my blog? BlogLovin is somewhat monolithic. They use the blog feed, and a BlogLovin URL with embedded token, to process / validate blog claims - and their diagnostics, when a claim is a problem, are not always effective. Some blog feeds can be validated, yet not be found by BlogLovin. And other feeds won't validate.
What Blogger won't tell you