Ok, don't panic. This is probably because you have registered to join a community but have not yet been approved by the people in charge. You are on their to-do list, but if it's been a while and you want to give them another nudge, just re-register, verify and they'll receive another email asking them to approve you. Alternatively if you have a friend who is already a member, ask them to invite you, and you will gain access right away when you accept the invitation.