SMTP error or can't find mailbox

i have an NEC 780, set up for wireless, it will surf the net and will recieve mail but depending on how i change my settings for mail reception i either get the message "SMTP error" (not the exact message) or "can't find mail box". i've been to earthlink, my IP, checked and rechecked my setttings. actually, i'm using the same settings i used for dial up and they sent and recieved my mail fine.

thanks for the help

gee

Were you able to find an answer for the outgoing mail setting through Earthlink? I'm having the same problem on my Jornada 720. If so, can you email me at adamy69@aol.com?

Thanks!

Adam