"hey paul, what version of mac OS are u using and what browser?"
Problem gone. All browsers (Firefox, Mozilla, Omniweb, IE), mail programs (Entourage) with Mac (Tiger) It seems that SMTP was not working (in the middle of the night here in Japan) and so the MAC could not use the password stored in the keychain and kept asking. I could send from webmail.
By the way, of all mail programs I tried, I find Mozilla best (even than Thunderbird, as Thunderbird does not always render incoming html mail and leaves out images. I find Entourage too busy (it was with a discount version of Offcie that expires after 6 years).
Thanks for the response.