Is this when you are trying to sign up that you get a link fail message? Make sure the + sign is in the url (as below).
If you are still having problems, then I would suggest posting your query in the forum as more people will be able to help.
It's awkward trying to fully answer your question in this section as I can only answer once and it would be helpful to get more details about what is going wrong. For instance, is this a sign up issue or something that is happening when you are adding amazon products to your hubpages?