I'd need to reproduce the issue. Can you send me the email with the link that goes to the 404 error? 404 means page not found, so it is something wrong with the link itself.
In order to fix any issue, you need to be able to reproduce it. Otherwise you wouldn't be able to test if you have fixed it even if you did try to do something. At this stage, when a problem is first reported, you need to work on doing whatever is necessary to reproduce the problem. If you follow the same steps as the user, then you should get the same result.
Once you can send me steps to reproduce, then I'll be able to get it resolved for you, but I really need to see it first to diagnose the cause and test to make sure I've fixed it.
Did this help? Tips are appreciated...
