Hi Petra Gruenig. Once you invite your family members through your account settings, they should receive an email with a link to sign-up. They should not be asked for a credit card. If you've sent them the link and they are having problems, please email us at support@grokker.com and let us know who the users are (their email addresses). We can help resolve the problem. Thanks!

Hi Petra Gruenig. As an Aetna user, you are allowed to invite family members to join Grokker. They would then have free access to Grokker like you do. To do this, you go into "Account Settings" and you'll see an area in the middle of the screen to invite family. I hope that helps.