How-to's
Steps to add a sender address to address book
In short: adding a sender to your contacts or safe-senders list tells your mailbox provider the sender is trusted, which helps their mail reach your inbox. Steps for each major provider and anti-spam service are below. Note that this is a ...
Message Headers
Understanding message headers In short: every email carries a hidden header block recording where it came from, the servers it passed through, and—most usefully today—whether it passed authentication. Steps for each major provider are below; if a ...
How to warm up a sender domain
In short: warming up a sender domain means gradually increasing your email volume—starting with your most engaged contacts—so mailbox providers learn to trust you. Authenticate first (SPF, DKIM, DMARC), ramp over about four to six weeks while ...
How to create a custom return path address
In short: a custom return-path address makes your bounce (envelope-from) domain match your sender domain, which is what lets your mail achieve SPF alignment and pass DMARC. Set it up by adding one CNAME record to your DNS and verifying the domain in ...