651? Not sure if error..

[-Ryuki-]

I actually don't know what this is, and guilty-as-charged, I'm trying to play on my friend's account. Would anyone happen to know what this is? A small window pops up after inputting the credentials and I can't quite comprehend the dialogue. All I know is, I'm supposed to input something, but not knowing WHAT to input, I click the left button and "No.651" shows up, then goes back to the SEGA ID input window.

[Dragwind]

Does he use his account on another computer? If so, that could be the problem. Apparently beta accounts can only be used on one PC, and if you try to log into another one, you have to input some kind of code/key.

[-Ryuki-]

Does he use his account on another computer? If so, that could be the problem. Apparently beta accounts can only be used on one PC, and if you try to log into another one, you have to input some kind of code/key.

Explains plenty. Thank you Drag~