Tuesday, November 24, 2009

Email problem: 503 Need Rcpt Command

SkyHi @ Tuesday, November 24, 2009
I've started taking a closer look at the bounces I get from my monthly mailout. Bounces from hotmail accounts start off by saying 'user unavailable' and then 'user unknown', so I wrote that off to exactly what it says -- the mailbox isn't available because there isn't a user by that name.

But today I read a little further and noticed a 503 error -- "Need Rcpt Command". Here's all the pertinent info:

----- The following addresses had permanent fatal errors -----
(reason: 550 Requested action not taken: mailbox unavailable)

----- Transcript of session follows -----
... while talking to mx2.hotmail.com.:
>>> DATA
<<< 550 Requested action not taken: mailbox unavailable
550 5.1.1 <our_customer@hotmail.com>... User unknown
<<< 503 Need Rcpt command

Now I should point out that we have no problem sending to the vast majority of hotmail accounts, and it IS possible that these few are, in fact, dead and gone, and that the 503 business is simply misleading. I tried Googling this error, but nothing seemed to address this in a way I could understand.

Can anyone here shed some light on this? And on a way to avoid this, if indeed there's a real hotmail user at the end of this chain?

A bit cheeky, but why not try emailing one of the users from a test Hotmail account to see if it bounces? Doesn't need to be linked to your business, just send a blank email from some random Hotmail address. Then you know whether there is a problem or not.

Is it always the same email addresses that fail? Are you sending all the emails in one go? Maybe Hotmail implements rate-limiting or something and is just stalling.

When sending email, you receive an immediate bounce such as the following:

Subject: RE: XXXXXX - October 27, 2005
Sent: 10/31/2005 12:40 PM
The following recipient(s) could not be reached:
'John Doe' on 10/31/2005 12:40 PM
503 valid RCPT command must precede DATA

This means you must check your email before trying to send mail meaning that our mail server requires authentication, which can be achieved using one of these methods:

A) Pop before smtp -- check your email for new mail before trying to send email. This adds your IP address to a relayhosts file and allows any email to be sent from that IP address for up to 30 minutes. After 30 minutes you have to authenticate again.

B) Configure your email client to authenticate automatically by checking the "my server requires authentication" box in your email configuration. You will be able to send mail without having to "pop" your mail box first.

If using MS Outlook, please try the following:

1) Open outlook
2) Go to Tools/Email Accounts
3) Select the Account with the trouble and click Change
4) Click on More Settings
5) Click on Outgoing Server Tab
6) Click "Outgoing Mail Server (SMTP) requires authentication" and make sure "Use same settings as incoming mail server" is selected (see attached image)
7) Click on "Advanced Tab"
8) Set outgoing Port (SMTP) to 25
9) Click Ok and then Test Account Settings

If it fails on send then repeat starting from 7.

7) Click on Advanced Tab
8) Set outgoing Port (SMTP) to 587 (See attached)



This usually is a result of the mail server requiring authentication.
If you are using Outlook 2003, here are the steps to enable authentication:

Watch the Outlook 2003 Tutorial!
  1. Open Outlook
  2. Go to Tools | Email Accounts
  3. "View or change existing e-mail accounts" should already be marked
  4. Click Next
  5. Select the Account with the trouble and click Change
  6. Click on More Settings
  7. Click on the Outgoing Server Tab
  8. Click "My outgoing server (SMTP) requires authentication" and make sure "Use same settings as my incoming mail server" is selected
  9. Click on the Advanced Tab
  10. Set "Outgoing server (SMTP):" port to 26
  11. Click OK and then Test Account Settings
  12. If everything is fine and reports no errors,
    • Click Close.
    • Click Next.
    • Click Finish.
  13. If an error does occur, it will switch to the Errors tab and display the error
Note: If you are still having errors, make sure your login username is your full email address and that the password is correct.


Your message did not reach some or all of the intended recipients.
Subject: Insert files as printouts
Sent: 1/1/2009 12:12 PM
The following recipient(s) cannot be reached:
dest@host.com’ on 1/1/2009 12:12 PM
503 Valid RCPT command must precede DATA
Generally, when you get this error when sending a message from microsoft outlook, it is because you did not enable authentication for outgoing emails.
To fix this error open the outlook “tools menu” and select “account settings” , from there select “Change” while selecting the account you want to use from the list. Now click the “More settings” button and select “outgoing server”, click “My outgoing server (SMTP) requires authentication” and keep “Use same settings as for my incoming mail server”
Press Ok , next , finish, close, die
try it now, it should be working