Everything we know, written down.
12 guides on why business email fails and how to fix it — the same explanations we give clients, minus the invoice. Each one answers a single question, cites its sources, and is also available as plain Markdown for anyone whose reader prefers that.
Diagnosis
The records
What are SPF, DKIM and DMARC, in plain English?
What each of the three email authentication records actually does, how they work together, what a working set looks like, and the order to set them up in.
My DMARC is set to p=none — is that enough?
p=none is monitoring mode. It satisfies Gmail and Microsoft's minimum, collects reports, and stops precisely zero spoofed emails. Here's how to use it properly and move past it.
What is the SPF 10-lookup limit and how do I fix it?
SPF evaluation is capped at ten DNS lookups. Go over and the whole record fails — not just the last entry. How to count yours, and the four ways to get back under.
The rules
What does Gmail require from senders?
Google's February 2024 sender requirements in plain English: what every sender must do, the extra rules for bulk senders, the 0.3% spam threshold, and what a small business actually has to change.
What does Outlook require from senders?
Microsoft's May 2025 requirements for high-volume senders to Outlook.com, Hotmail and Live — what's required, what the 550 5.7.515 bounce means, and how it differs from Gmail's rules.
Your platform
Why do my Xero or MYOB invoices land in junk?
Accounting software sends invoices using your business name and its own servers. Here's why that fails authentication, what it costs you in unpaid invoices, and the two ways to fix it.
Why don't my website form and order emails arrive?
Contact form notifications, order confirmations and password resets fail more often than any other mail a small business sends. Why that happens on WordPress, Squarespace and Shopify — and how to fix it properly.
How do I set up email authentication on Google Workspace?
A checklist for SPF, DKIM and DMARC on Google Workspace: the exact records, where DKIM hides in the admin console, and the mistakes that make it look configured when it isn't.
How do I set up email authentication on Microsoft 365?
SPF, DKIM and DMARC on Microsoft 365: the records to publish, why DKIM uses two CNAMEs instead of a TXT record, and the migration leftovers that break it.
Reference
What do all these email deliverability terms mean?
Plain-English definitions of SPF, DKIM, DMARC, alignment, selectors, MTA-STS, BIMI, ARC, soft fail, aggregate reports and the rest of the vocabulary.
What does all this mean for an Australian small business?
What the 2024 and 2025 sender rules mean for an Australian business: .com.au domains, invoice redirection fraud, spam law, and what to actually do about it.
Or skip the reading and check your domain.
Machine-readable index of everything on this site: /llms.txt