Phantasy star online(dreamcast)help

[Piendo]

I just bought this for the dreamcast and having trouble starting when i start it up it ask for a serial code and key code or something, now bought it used but came with the booklet and case but the serial codes to long and im looking for an 8-digit code somewhere.Anyone know anything about this or just the game in general and how good it is minus the online?

[Logicdustbin]

I'm pretty sure it is the long code on the back insert, under where the disk goes in the case.