Why can't I send mail, but I can receive it? Should I delete and re-install my yahoo e-mail account?
Is it also possible to sync with that account to get the older e-mails in that account?
Like FOREVER29 adviced, go to the VZ BIS website, loggin or register if you haven't. Under help look for service books and send them. This will fix your email problems. Also make sure that under your Yahoo account pop/imap forwarding in ON.
I think you can send with correct Service Books. However, you can only receive with fully Registered Host Routing Table (see Settings, Advanced). Select Register Now.