Signature mismatch/OpenID login failed.

I have setup two drupal sites for some testing purposes.
http://pragyan.org/op
http://pragyan.org/rp

I have set the permission for anonymous user to view the user profile.
But when I use the op account openid to sign onto say, plaxo.com I receive a signature mismatch error.

Following steps can be used to reproduce the error::

1) Login to pragyan.org/op with a openid.
So now we have a account on pragyan.org/op

2) Now login to pragyan.org/rp using the openid of the user created in the first step.(i.e, something like pragyan.org/op/user/4)
This step fails to log me in to pragyan.org/rp

Also I tried to login to plaxo.com using the pragyan.org/op openid. There also the log in fails wherein the error message that plaxo displays is
"Unable to verify the specified OpenID: signature mismatch."

Even an account created on op site using a direct signup fails to be authenticated as openid on rp.
Though a similar setup is working fine for me on my laptop.