Use another service to log in
Log in through the social network if you registered on this site, using the login of the social network.
If you are already registered on this site with an email used in social networks,
and you also want to log in through the social network login,
then log on to the site and add an entry through the social network on the page
"Manage your external login".
If you do not already have a login on this site, you can create it through the login of the social network.