Seeing "recipient getting too much mail" delays at Gmail?

Here's a question I get asked from time to time: What does THIS Gmail SMTP delivery temp failure error actually mean? Here's the error in question: 450, "4.2.1", The user you are trying to contact is receiving mail at a rate that prevents additional messages f…

Ask Al: What if domains don't match?

A friend recently asked me, "If sending domain is email-example.com and all URLs in the email body point to example.com, would that cause any deliverability issues?" I get this question often, so I thought it would be a good thing to write up and share here, for futur…

Verizon (Yahoo) launches new sender-focused portal

Verizon (AOL and Yahoo) just launched a new "sender focused portal," highlighting features like AMP for email, BIMI, Promotions and more. Check it out here . (And don't forget to keep an eye on their Postmaster blog , where they announce stuff like this. [ H/T: Ve…

ISP Deliverability Guide: Mail.de

Mail.de is a German provider of email services, founded in 2009 . I can't find any information about the size of their user base, but they seem to be in the top ten or top fifteen ranking of mailbox providers in the region -- not the biggest, but certainly large enough that…

Cómo complacer a Gmail, en Español

Guy Hanson de Validity explica, en español, lo que necesita saber sobre el envío de correo electrónico a Gmail. Clic aquí para saber más . Guy Hanson from Validity explains, in Spanish, what you need to know about sending email to Gmail. Click here to learn more . Este es un bu…

What identifies an email message?

Today, I'm trying to help a client answer the question of how Gmail decides in which tab to place a sender's email messages. That leads to the question of how does Gmail, or any other ISP, identify the sender or messages in question? Google, like most ISPs, does not exp…

Fastmail now supports BIMI

I'm not exactly sure when it went live, but I am now reliably informed that Australian mailbox provider (and owner of Pobox and Topicbox ) Fastmail now supports BIMI. Fastmail's Marc Bradshaw was kind enough to confirm for me: They do not have a FAQ or support page on…

Abusix: 8 ways on how ESPs and DNSBL providers can collaborate better

Steve Freegard, Sr. Product Owner Abusix Intelligence recently shared his thoughts on how ESPs can better position themselves with regard to blocking list (DNSBL) issues. He recommends segmenting traffic by IP address, using different subdomains or domains for each customer, li…