In the case of joining Initiative Q you always need to use the Q invitation link. You need the person who invited you has might use up all of their invites for the Initiative Q. You can check with them to visit if they have really invited any of their mutual friends who might send you the valid invitation link.
Here we offer you two other methods to get invited by the Initiative Q:
You need to go to the Initiative Q’s Facebook page and at the Twitter page and check which of your friends has already follow the Initiative Q page. They might already be listed into it.
You can also submit your post on the social media and can ask with your friends so by that any one of them will help you on it to invite you.