If you are trying to connect with your club and that club is grayed out on the selection box, this means you have previously requested a connection and that connection was denied by an admin at your club. To prevent constant spamming of admins, you are not allowed to reinitiate the connection process.
However, your admin can still approve your original connection request. Admins, should login on the website, go to Users and search for Denied Users. From there they can locate your request and approve it.