update to latest openid library
release v3.3.4
This solves a problem with doubly-encoded identity URLs

I have not checked where exactly the problem is but I was getting an
URL-encoded identity_url when trying to log into a subdomain blog
(https://tips.at.gg3.net/) on a multisite wordpress installation. The
plugin worked just fine on the main blog (https://at.gg3.net/).