DDOS is often just partially. They attack the weakest part. I thought it's the authentication server (Battle eye's?) in this case. But mind me if i'm wrong and dito for possible typo's cause i'm not English speaking. Also if the attack is heavy but not heavy enough there's still the possability you can login but others not, and so on.

All your comment means is you don't understand what DDOS actually means. DDOS attacks are usually intermittent. You might want to Google what they are and edit your comment asking why you are getting into the game, then kicked at random times. You probably also need to Google "intermittent" too though.