If you have a dot in your user name, such as first.last.myopenid.com, you can't use the normal link to register; you will need to click the link to manually enter your ID, then enter it manually at the openid site.

I have this problem, and found the answer somewhere on the stackoverflow site.

For more information, see this discussion:  [stackoverflow openID problem][1]


  [1]: http://meta.stackoverflow.com/questions/71584/login-via-myopenid-does-not-work/96080#96080