Email error 503, how to solve?

Question

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 Requested mail action okay, completed

• and some others...

Answer 1

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.

Answer 2

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