Received Invitation! But cant play

Hello Guys ! I am one of the Gunrox players I received an email from Enkord " We at Enkord would like to invite you to try out new version of our latest game in development: 

Totem Tribe II: Jotun Alpha 6 (invite-only version) 

im so excited about this game, because i love Enkord. So i downloaded the game, create an account using the email i received the invitation. But i can't play. It says "Unfortunately, we are able to only let a limited number of players into the game at the moment... .  Wait until we invite you. "   

I already received the invitation. why cant i play? please help.   

Thanks berserker. You never let me down. 

After playing this game for several hours, it is just awesome! The story is amazing and unpredictable. It just makes me feel like i'm truly a real character in this game. Custom character is just wonderful too and a lot more. Most importantly, I can also learn English while playing this game too. It might be the second best game i have ever played after Gunrox. Hopefully, i can play this game more. Thanks ENKORD team. 

I had the same problem , can you help me too?