Sending and receiving.
WHAT HAPPENS WHEN MAIL IS SENT
The client submits it to a mail server That server looks up the recipient domain's mail records It connects to the recipient's server and delivers The recipient's server accepts or rejects
WHAT DETERMINES WHERE MAIL GOES
The mail records for the domain.
WHAT THE TWO RETRIEVAL APPROACHES ARE
One keeping mail on the server, synchronised across devices One downloading and typically removing it
WHY THAT MATTERS IN SUPPORT
The second produces reports of mail disappearing from other devices.
WHAT TO RECOMMEND
The first, for anyone using more than one device.
WHAT AUTHENTICATION RECORDS DO
Declare which servers may send for a domain Provide a signature verifying messages State what receivers should do with failures
WHY THEY MATTER
Without them, mail is frequently rejected or filtered.
WHAT TO CHECK WHEN MAIL IS NOT DELIVERED
The bounce message, which usually states the reason precisely.
WHAT CAUSES MOST CLIENT SETUP FAILURES
Username not being the full address Outgoing authentication not enabled Wrong port or encryption setting
