Gator said:
I'm trying to send a email and i received a message: 550 please
configure your mail client to use authentication
This means the SMTP (outbound) server you're connecting to wants a username
& password to let you send mail through it - very common given the number of
spammers who would love to send mail through an open relay server. Contact
your ISP/mail host for more info, but in general, the option to authenticate
is in your mail account properties - you haven't mentioned your v. of
Outlook, which makes a big difference. Look around; you should find it. The
login info is usually your same POP account credentials, presuming you're
sending mail through your mail host's SMTP server & not someone else's.