Using open auth with FB, Twitter and Google.
It seems I've set up the apps correctly as when I try any of them I get returned to the RegisterExternalLogin.aspx page. Then things don't go the way I expect them.
I haven't changed any of the code on this page that was generated by VS2013.
It shows the email address the app has pulled from FB, etc. and then asks the user for "a" username for the current site (my site). Presumably this would be the user name that user registered with on my site. So when such a name is entered I get the error message from a validator on the page "The E-mail supplied is invalid."
I've no idea what this means. Is the email address supplied by the app supposed to be the same one the user used when signing up on my site?
I know this error can occur when an email address is already in the db table but I'm sure this is not the case here. The site has not yet been deployed and there is a small number of test users only.