I think I've figured it out now. I had a limited knowledge about Redis earlier, so I decided to learn about it properly. I managed to backup the database by following this guide http://www.tutorialspoint.com/redis/redis_backup.htm if anyone else is stuck on the same thing as me.
A quick firewall-cmd --zone=public --add-port=4567/tcp --permanent and firewall-cmd --reload later
And there we go.
Thanks @rbeer for the information about nodejs versions. I did not see the indicator that you did obviously.
Very nice! Glad to see it working now.
And, don't you worry! I was tearing my hair out for about an hour, when I stumbled upon that error some weeks ago.