I am testing this openid plugin and running into error for some openid providers.
Error says - "OpenID login failed: Bad signature"
I am getting successfully redirected to openid provider, but on way back, I am getting above error.
Also some providers are working fine like blogspot.
As far as error is confirmed for Google & Yahoo login.
U can test yourself as my test-site is publicly accessible - http://openid.rtcamp.info/