When a mailbox provider rejects or defers an email it sends back a message explaining why. Those messages begin with a three digit number (starting with a “5” for rejections and a ̶…| Word to the Wise
What is Deliverability Week? Al Iverson decided it should happen, and asked a bunch of deliverability folks to share some of their thoughts about the deliverability industry – why do we do th…| Word to the Wise
Happy 2024, everyone! We’ve released a shiny new tool to let folks self-check a lot of common questions we see about email requirements. Go to AboutMy.email and send an email to the email add…| Word to the Wise
Seen this recently? 451 Message temporarily deferred due to unresolvable RFC.5321 from domain; see This is Yahoo doing some extra work to identify that the 5321.From domainThe return-path, aka the …| Word to the Wise