7 Replies Latest reply on Nov 2, 2015 8:37 AM by Jason Scott

    Major bounce errors with sbcGlobal

    Jason Scott

      We have a lot of small business using domains sbcglobal.net, which is now part of AT&T.  We are having issues with emails getting through.  It doesn't matter the email content or from address.  They always hard bounce with the error code "553 5.3.0 flph399 DNSBL:RBL 521< XXX.XXX.XXX.XXX >_is_blocked.__For_information_see_http://att.net/blocks".  Obviously they are getting blocked.  We've limited sending to sbcglobal email address to only-as-needed basis.  Had them send an email to us then reply using the outlook plugin so the reply came from our marketo server, which has a dedicated IP.  We can send emails without issue through our outlook server.


      Have you had issues with sbcglobal?  What did you do to fix it?

        • Re: Major bounce errors with sbcGlobal
          Mike Reynolds

          Emails being bounced can sometimes still get successful deliveries if the bounce was the result of a spam filter watching a spam trap or blacklisting service. If that gets de-listed with the spam trap or blacklist service, you could get successful deliveries again. Don't count on it. But it's possible. You could also try maintaining a directory of leads that are bouncing your emails. This would show you which leads you need to prune from your database

          Maintaining a Directory of Leads Bouncing Emails

          • Re: Major bounce errors with sbcGlobal
            Dan Stevens

            Good luck sending emails to anything AT&T owned.  For us, we have never been successful in sending Marketo emails to AT&T recipients.  In fact, we have a few clients that block ALL emails from Marketo - regardless who the sender is.

              • Re: Major bounce errors with sbcGlobal
                Mike Reynolds

                Dan Stevens Our Deliverability team immediately responds to any Blacklisting or SpamTrap hit that occurs to request de-listing. AT&T does have more strict filters than some others, but there is no reason to say that AT&T blocks ALL emails from Marketo as a rule. I'm looking at another customer's instance right now, ran a quick smart list, and it shows thousands of leads who have had successful deliveries with AT&T email addresses.


                Email senders develop a reputation with email service providers based on sending behavior. Things like sending emails to leads that have invalid email addresses or have continually bounced your emails, sending to leads who have never taken action to open or click your email, these can play into your sending reputation and negatively effect your deliverability rates. Different email providers have different settings, but with good lead database cleaning and maintenance, you can improve your reputation to ensure good deliverability rates, even with AT&T. If you've had bad rates with them, it's likely due to sending reputation and is definitely something to look into closely within your account.


                Marketo has a large number of resources devoted to this. Here are some of them that are the most useful:

                Email Deliverability Resources: http://www.marketo.com/email-deliverability/

                Troubleshooting Email Deliverability: https://nation.marketo.com/docs/DOC-1948

                Quarantined IP Range: https://nation.marketo.com/docs/DOC-1381

                Blacklist Remediation: https://nation.marketo.com/docs/DOC-1148

                What is a spamtrap: https://nation.marketo.com/docs/DOC-1144

                What is a Blacklist: https://nation.marketo.com/docs/DOC-1145

                Blacklist Deep Dive: https://nation.marketo.com/docs/DOC-1116

                Successful Reconfirmation: https://nation.marketo.com/docs/DOC-1149

                  • Re: Major bounce errors with sbcGlobal
                    Dan Stevens

                    Mike, I never said that AT&T blocks all Marketo emails.  I said that we have some accounts - Centrica in the UK is one - that has active blocks of all emails sent from Marketo.

                      • Re: Major bounce errors with sbcGlobal
                        Mike Reynolds

                        If you have email providers blocking all Marketo emails, you could try branding your envelope_from headers in the emails. This would allow you to put your company's domain branding into the HELO/Hostname headers within an email, which will brand it more than just setting up a branding link under Admin > Email or by setting up DKIM/SPF. This will help represent the email as having come from your domain as opposed from a Marketo server. It's still sent from the same IP address, so if they're using the IP for identification, it may not help, so I can't guarantee results, but it could help here.


                        We don't have any documentation specifically for this, but it's mentioned in Step 3 in this doc: Technical Tip - Set up DMARC in 5-Easy Steps


                        Disclaimer: This is included with Dedicated IP's, but not all levels. Check with your Customer Account Manager to see if you have the correct type of Dedicated IP (Gold).

                  • Re: Major bounce errors with sbcGlobal
                    Jason Boehle

                    We had problems with some of the smaller ATT domains a couple of months back, specifically sbcglobal, prodigy, pacbell and a few others. For whatever reason we were getting deliverability to ATT.net, but not the subdomains.


                    The Marketo deliverability team admitted they were having deliverability issues into those domains and asked to suppress those until the issues could be resolved. When I got word the issue had been fixed, I slowly added openers only, then scaled up the volume to the rest.


                    That seemed to fix any the issues we had and I have not experienced deliverability problems since. Here are the ATT sub-domains that were suppressed.











                    Hope this helps,


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