Email Delivery

A Step-by-Step Checklist for Email Delivery Problems

Quick Answer

Start by identifying whether the problem is sending or receiving, affects one user or everyone, and whether there is a bounce message. Those three answers usually point directly to the right area to check next.

Email delivery problems have many possible causes, but a short set of scoping questions usually narrows the list quickly before you need to look at any specific record or setting.

Common Causes

Jumping straight to DNS changes before confirming the scope of the problem.
Not checking whether a bounce message exists before assuming it is a silent failure.
Troubleshooting as if every delivery issue has the same cause.

Safe Troubleshooting Steps

Determine if the issue is outgoing, incoming, or both.
Determine if it affects one user or the whole domain.
Check for a bounce message on either end.
If outgoing: check sending limits and SPF/DKIM.
If incoming: check MX records, filters, and mailbox storage.
If domain-wide: check DNS records and the Admin console for domain-level alerts.

What to Verify

You know the scope (who/what is affected) before investigating causes.
You have checked for a bounce message on either end.

When Professional Help May Be Useful

If you have worked through this checklist and the cause still is not clear, it is usually more efficient to have someone review the specific message headers and DNS records directly.