If you have not yet redeemed your access token, your Game license won't be active yet, so you will need to use this URL to redeem it: https://hub.joincyberstart.com/sign-up. If you see an error claiming your game token has expired, then this is because you have already registered the token and can move on to the next step of logging in. 
Once you have redeemed your token and activated your license, the sign-in URL will be https://hub.joincyberstart.com/sign-in. Remember to log in using the email address and password you entered to register the game token. 
If you are using the correct link, and you're still having problems, could you please email support@joincyberstart.com with your question? The folks there are better placed to help with questions related to the CyberStart Game platform.