Error 550 or 504 when sending mail

Error 550 or 504 when sending mail to AOL, HOTMAIL, MSN, etc...

The typical 550/504 error report looks like this:

Delivering via flmx-2.tampabay.rr.com:25
< 220 flmx06.mgw.rr.com ESMTP Welcome to Road Runner. NO UCE *** FOR AUTHORIZED USE ONLY! ***
> HELO 242852hfc04.tampabay.res.rr.com
< 250 flmx06.mgw.rr.com Hello 242852hfc04.tampabay.res.rr.com [24.28.52.4], pleased to meet you
> MAIL FROM:<xxxx@tampabay.rr.com>
< 550 5.7.1 Mail Refused - res.rr.com - See http://security.rr.com/rrDynamic.htm

The explanation of the failure to deliver the message is in the last string (please follow the url above). The mail has been rejected because the mail server does not accept mail from dynamic IP addresses. To bypass this restriction, you should send mail to these addresses via your ISP's SMTP server. Please open the Settings / Common Settings / SMTP menu in Atomic Mail Sender and specify the mail server address there (see the screenshot below). It should help.

(Usually, you should not select "ESMTP Authentication" and "POP before SMTP". It is required only if your ISP requests authentication before sending mail.)

Error 550 / 504 should be fixed now

 

See also other error types:

How to get the full version of Atomic Mail Sender

To order Atomic Mail Sender, simply click the link below or go to this section to learn more about alternative payment methods. Also, before ordering, you can get the downloadable version of the program here.