A friend recently asked why some of his associates’ emails are being trashed to his Spam / Junk folder. Of course he knew his associates as people who would not engage in such illegal activities like sending spams.
We did a quick check and noted that Yahoo had been having problems with its anti-spamming filter lately.
Erroneous mail rejections at Yahoo had been reported as happening since last month. It just so happened that our friend is using a Yahoo webmail. And Yahoo’s spam filter was playing up.
The problem with Yahoo’s anti-spamming filter had been reported in the Spamhaus website. Spamhaus reported that Yahoo had issued the following announcement:
We have received reports that 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. We shall post an update once we have resolved the issue.
Yahoo’s HELP pages should provide some guide on how to place email addresses in the users whitelist.