Activation link not working

[DisasterDotCom]

I'm getting a number of users saying that their activation links don't work. I verified it myself... it seems as if you wait a day to activate, the link comes up with an error. Any ideas? Thanks!

[Lynne]

Activation links are only good for 4 days (I am pretty sure). A cron job runs to remove them - /core/includes/cron/cleanup.php