I try all the solutions but if I try to enter as superadmin in one site mapped with MU domain mapping I'm redirected on:
http://higringo.com/wp-login.php?redirect_to=http%3A%2F%2Fhigringo.com%2Fwp-admin%2F&reauth=1
If I try to enter admin user and password I'm only redirected to the site and not to the admin panel for this site.
If I take out the domain mapping for this site after I can enter on admin panel.
Any ideas?
http://wordpress.org/extend/plugins/wordpress-mu-domain-mapping/