Customers not receiving your invoices? Why invoice emails go to spam

Updated 10 November 2026 · by Mohamed, Growth with MK

"I never got the invoice" is one of the most expensive email problems a small business can have, because it quietly delays payment. Before changing anything, work out who actually sends your invoice emails. The fix depends on it.

Step 1: find out who sends them

Send an invoice to yourself at a Gmail address, open it, and click the three dots → Show original. Look at the From: line and the SPF, DKIM and DMARC results at the top.

From the accounting app's own address. Xero's standard invoice emails, for example, come from a Xero address (post.xero.com) with your email as the reply-to. QuickBooks' standard emails come from an Intuit address. Your domain's DNS doesn't affect these, so adding Xero or QuickBooks to your SPF record won't help.
From your own domain, for example accounts@yourbusiness.co.uk. Then your domain must authorise whatever sent it: your mailbox, or the app if it supports sending from a verified domain.

If the app sends from its own address

Check the customer's address. Accounting apps show whether an email bounced. Look at the invoice's history or activity log.
Ask the customer to check junk and quarantine. Larger customers on Microsoft 365 often have a quarantine their IT team manages. Ask them to allow the app's sending domain.
Keep the message plain. A short, personal message with the invoice number and amount filters better than a template full of links.
For repeat offenders, send the PDF from your own mailbox. That uses your domain's authentication, so make sure it's set up (below).

If invoices come from your own domain

Run the free domain check. It shows whether SPF, DKIM, DMARC and MX are in place.
SPF: one record listing your mailbox provider and any app the help centre tells you to include.
DKIM: on in your mailbox, and in the app if it offers domain verification.
DMARC: v=DMARC1; p=none; rua=mailto:you@yourdomain at _dmarc, tightened later.
Re-test with Gmail and, if your customers are businesses, an Outlook.com address too.

Habits that get you paid faster

Confirm the accounts email address when you take on a new customer, not after the first late payment.
Use a consistent subject line: "Invoice INV-1043 from Your Business, due 30 Nov".
Turn on automatic reminders in your accounting app.
Add a payment link so the invoice can be paid straight from the email.

Customers mainly on Outlook? See emails going to junk in Outlook.

Frequently asked questions

Should I add Xero or QuickBooks to my SPF record?

Only if their help centre tells you to for a feature you use. Their standard invoice emails are sent from their own domain, so your SPF record doesn't apply to them.

The customer says the invoice isn't in spam either. Where is it?

For business customers, check their quarantine (Microsoft 365 and many filters hold suspicious mail there rather than in junk). Also confirm the address in your app has no typo and hasn't bounced before.

Is it better to attach a PDF or send a link?

Both work. A link to pay online is convenient. A PDF attachment from your own mailbox is a good fallback for customers whose filters block the app's emails.

Can a missing DMARC record stop my invoices arriving?

If invoices come from your own domain, yes, it makes them more likely to be filtered, particularly by Gmail, Yahoo and Outlook.com, which all now ask senders to authenticate.

Check your domain in 10 seconds

See your DMARC, SPF, DKIM and MX score out of 10, with fix steps for your email provider.

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