Email plugin throwing SMTP error code 554

[eluser]taewoo[/eluser]
HI everyone.

I'm a newbie to CI, so please bear with me.
I managed to integrate FreakAuth into my CI installation (by the way, it's DOPE). I am testing the user registration part of it and I'm using SMTP server I setup on dreamhost. (I tested the account to make sure it can send and receive just fine via outlook)

I do a debug message and I am getting this error:

Code:

220 spunkymail-a11.g.dreamhost.com ESMTP

hello: 250-spunkymail-a11.g.dreamhost.com
250-PIPELINING
250-SIZE 40960000
250-ETRN
250-STARTTLS
250-AUTH PLAIN LOGIN
250-AUTH=PLAIN LOGIN
250 8BITMIME

from: 250 Ok

to: 554 : Recipient address rejected: Access denied

The following SMTP error was encountered: 554 : Recipient address rejected: Access denied

data: 554 Error: no valid recipients

The following SMTP error was encountered: 554 Error: no valid recipients
221 Error: I can break rules, too. Goodbye.
The following SMTP error was encountered: 221 Error: I can break rules, too. Goodbye.
Unable to send email using PHP SMTP. Your server might not be configured to send mail using this method.

User-Agent: CodeIgniter
Date: Fri, 25 Jan 2008 21:12:22 -0800
From: "Redmol.com Redmol Administrator"
Return-Path:
To: [email protected]
Subject: [Redmol.com] Account activation info
Reply-To: "[email protected]"
X-Sender: [email protected]
X-Mailer: CodeIgniter
X-Priority: 3 (Normal)
Message-ID: <[email protected]>
Mime-Version: 1.0

What does this mean and how do I remedy the situation?

PS: I made sure port 25 is open and working (via outlook)

[eluser]Ahmed Nuaman[/eluser]
Does the recipient exist? What normally happens with most SMTP server is that they check who the email's going to and instead of sending it and having an email pop back saying "no-one's here", they do a check to see if this email exists.

There is a way to turn this off, but the main error is that:

data: 554 Error: no valid recipients

[eluser]taewoo[/eluser]
[quote author="Ahmed Nuaman" date="1201365626"]Does the recipient exist? What normally happens with most SMTP server is that they check who the email's going to and instead of sending it and having an email pop back saying "no-one's here", they do a check to see if this email exists.
[/quote]

Yeap. It exists alright.

[eluser]Unknown[/eluser]
I have a same error.
My smtp server is postfix.
who can send mail by stmp protocol?

by the way,I can send mail by phpmailer with same configuration

[eluser]taewoo[/eluser]
THis was mail protocol issue. If sending from the host itself, it was sendmail. If sending from external (i.e. from my laptop) it's smtp