It sounds as though you have an email programme problem. The 404 error is very common and will be displayed whenever a site cannot be found. It might be that the site server is down or no longer exists, but if it happens with every link, then that might be your software at fault.
Please start a fresh topic in our Internet and Browser forum. The people there are more expert than myself on this topic and will be able to deal with your problem quicker than I can.