<p>When I try to login to this site using my yahoo openid, it takes me to the yahoo site, I click "continue" meaning that i <em>want</em> to send my authentication details to stackoverflow.com and stackoverflow.com gives me the following error underneath the login text field:</p>

<p>Unable to log in with your OpenID provider:</p>

<p>failed to authenticate, returning Failed. Please ensure your identifier is correct and try again. </p>

```
```
public string UserDefinedField
{
    get { return _userDefinedField; }
    set { SetField(value); ChangedFields.Add(Fields.UserDefinedField); }
}

// Call this from internal methods and use the public property for other cases
internal string SetField(string userValue)
{
    _userDefinedField = userValue;
}
```
```
You
could
get the caller information by
examining the calling stack
but that is extremely slow (compared to the above) and I wouldn't recommend it.