Hi
Do not know why it's not working, but please follow this instruction to see if it's configured properly:
https://www.gavick.com/documentation/ge ... k-feature/You can add other login systems, but this is a customisation request, so all I can say is that You need to install extra social auhtentication plugins and modifie /html/mod_login/ to make it show (I'm sure instructions will be on social pages). Or You can simply replace login module to one which supports all of them.