Is it possible to allow users to comment by logging in using their WP/FB/Twitter/G+?
Reply button stopped working, so I followed the sticky thread and disabled Jetpack comments. Now the reply button is working. Earlier it used to work with Jetpack comments. Now after disabling Jetpack comments, the option to log in via FB/Twitter/G+ is gone.
You can't use wpDiscuz with Jetpack comments. I think you even didn't see that the comment form was Jetpack form not the wpDiscuz form. wpDiscuz can't work without its own comment form. When you enable Jetpack it replaces wpDiscuz comment form with Jetpack form. You can use WordPress Social Login plugins. Most of those compatible with wpDiscuz. Example:
Unfortunately, the plugin you have shared is not working. I have tried Nextend Social Login but I cannot see the login buttons. Any other recommendation?