Over the past few days Email Manual has received a couple of reports that delivery attempts to yahoo email accounts have resulted in bounce messages being returned by Yahoo quoting that the recipient was on the spamhaus PBL blocklist.

Upon investigation, Email Manual has found a post on the yahoo postmaster site with the following information:-

some senders are seeing intermittent IP blocks when sending to Yahoo! Mail, with the SMTP error message from us citing that the block was due to a Spamhaus listing — e.g., “553 5.7.1 [BL21] Connections not accepted from IP addresses on Spamhaus PBL.” (See our full list of SMTP error messages at http://postmaster.yahoo.com/errors/ .)

If your IPs are currently not listed on any Spamhaus blocklist but you are seeing this error, please be assured that we are looking into the matter.

Whilst this doesn’t appear to affect all senders or even the affected senders all of the time Yahoo are working on this error. This may result in higher than usual bounce rates on campaigns going to yahoo based addresses and this should be taken into consideration when reflecting on your campaign reports.

Email Manual will post again when the issue has been resolved and confirmed by Yahoo.

Update 05/06/09 – Yahoo claim pbl issue resolved.