Actually, the same thing is happening to me, and I have tried restarting my computer. I have logged in and played countless times without issue, and I seem to have no problem logging into Impluse using the same username and password.
Interestingly, I had logged in successfully twice in a row just before this, and each time my game crashed at the character select screen. Then the third time, I just couldn't log in anymore.
It's only been about ten minutes, so perhaps I'll just magically be able to log in again eventually? I guess I'll give it some time and see what happens.