What browser do you use, I would use google chrome if you haven't already got it. This could also be your java being a problem so you could try reinstalling it. Google Chrome Java ^^click them^^
I could not do anything on the plug.dj website for a while *Then I took an arrow to the knee*! *cough no* xD I discovered one of my extensions I was running on Chrome called Disconnect was pretty much disconnected me from the website xD
One of the problems I had with plug.dj (Now Fixed, Found the Problem) I had an extension called disconnect that loads pages faster, it was not allowing me to load anything on the plug.dj site. So it's possible for an extension in your browser to stop you from ... Welll signing in
I never heard of plug.dj What can you do? Meh is it really so good that I need to make an account there?
basically you make an account and join. Then you make a playlist and share music you have, from youtube and soundcloud. You can make playlists of your favourite artists and join all of us there.
It's quite fun if you've got the right amount of people in the same room. As long as you have a respectably long play-list everyone's happy!
We's got a real party going on here! Anticipation for Athion is building by the second! Join us at https://plug.dj/athion-network