I had the same problem. I can't really help you, because I myself tried to log off of mc and then back, on but it failed. I know that it has something to do with the fact that your minecraft logged in via the "access token." As I said, I tried to log off but now I can't log back on, not even on minecraft.net! I'm on Ubuntu Linux with my ISP being Verizon, so I'm sure that the OS and internet connection have nothing to with it.