Email error 503, how to solve?

I have problem sending emails, i checked the email sending error logs, and I found this:

RCPT RCPT TO:

503 This mail server requires authentication when attempting to send to a non-local e-mail address. Please check your mail client settings or contact your administrator to verify that the domain or address is defined for this server.

And this:

Sending unsolicited commercial or bulk e-mail to Microsoft's computer network is prohibited. Other restrictions are found at http://privacy.msn.com/Anti-spam/. Violations will result in use of equipment located in California and other states.

And following I dont understand what it means:

• DATA DATA 354+Start+mail+input;+end+with+.

• RCPT RCPT TO: 250开发者_Python百科 Requested mail action okay, completed

• and some others...

This SMTP server requires authentication. Depending on your provider, you either need to specify username/password or, if your host uses POP-before-SMTP auth, you need to check your email first and that action adds you to an authenticated list for some time so you can send replies.

This error means you need to authenticate against your SMTP server before sending out emails.