If you cannot collect on a link, IT MEANS that:

1) You've already collected on an identical link
2) You didn't wait long enough for coin amount to pop up before exiting
3) You've already collected on an identical link from the fan page
4) You've already collected on an identical link from your own email
5) The link has expired or reached the number of clickers - it is no longer available for collection
6) You refreshed your browser (this won't work because the first time you opened the link, your browser registered.