All guides

Why are my invoices going to customers' spam? (Square, QuickBooks, Invoice Ninja and other billing tools)

Last reviewed 2026-10-22 · Based on the official references linked below

Has a customer told you your invoice landed in spam, even though your ordinary emails arrive? Your billing tool may send through a different mail service. Start by checking which domain actually sent the invoice.

Authentication is one common cause of invoice delivery problems. Content, links, sender reputation, new domains, blocklists and the customer's own filters also matter. Fixing SPF, DKIM and DMARC does not guarantee inbox placement.

1. Find the invoice's real sending domain

Check the customer's email address, the invoice's delivery method and any bounce or delivery error first. If a copy reached spam, inspect that message. Otherwise, send a test invoice through the billing tool to an external mailbox you control.

In Gmail on a computer, open the invoice and choose More → Show original next to Reply. Google's header instructions show the steps. Note:

• From address: expand the sender details. Your business name can appear next to an address on the billing provider's domain.
• Reply-To: this is where replies go. Setting it to your business address does not mean the invoice was sent from your domain.
• Return-Path and DKIM signing domain: the return-path domain is checked by SPF; d= in a DKIM signature identifies the signing domain.
• Authentication-Results: look at the receiving system's spf, dkim and dmarc results, including the domains tested.

In your billing account, look for Email settings, Sending domain, Domain authentication or a connected Google/Microsoft account. Compare those settings with the actual received invoice. A company contact address or logo is not proof of domain authentication.

Microsoft's SPF reference explains the return-path check. Google's DMARC reference explains how it connects to the visible From address.

2. Choice 1: send as your domain and authenticate it

If the invoice's From address is [email protected], the service sending it needs authentication for that route. Turning on DKIM in Google Workspace does not sign mail sent separately by a billing provider.

1. Identify the mail provider. Is the tool using your connected Workspace or Microsoft 365 mailbox, its own mail servers, or a separate service such as Postmark? Follow that provider's custom-domain instructions.
2. Review SPF. If the service uses your domain for its return-path, include its documented sending sources in that domain's SPF policy. Keep one SPF record per domain and preserve your other legitimate senders. Some services instead provide a dedicated return-path subdomain and CNAME; follow their exact instructions.
3. Enable custom-domain DKIM. Copy the provider's generated TXT or CNAME records to your DNS host, then complete verification and enable signing. Keep existing keys used by your other services.
4. Check DMARC alignment. At least one passing method must align with your visible From domain: SPF's return-path or DKIM's signing domain. Aim to configure both correctly where supported; they do not both have to align for DMARC to pass.

Do not add a guessed include:squareup.com or include:intuit.com. Adding a provider to the root SPF record cannot fix alignment if it sends using an unrelated return-path domain.

For example, Postmark's SPF guidance says a root SPF include is unnecessary for its default route. It offers a custom return-path for SPF alignment alongside custom-domain DKIM. The right setup depends on the actual sending service.

For connected mailbox sending, use our Google Workspace DKIM steps or Microsoft 365 DKIM steps, then test an invoice through that connection. If DMARC is new, monitor all legitimate senders before tightening the policy; do not weaken an existing policy just to hide failures.

3. Choice 2: send from the tool's own domain

If your tool supports it, use its default sending service with a From address on a domain the vendor owns. Keep your business name visible and set your business address as Reply-To where supported.

The vendor then manages authentication for its sending domain. You do not need to authorize those messages in your business domain's SPF record merely because they carry your company name. Your own domain still needs the right authentication for staff mail and any other services sending as it.

This can be simpler if you do not need a custom From address. It still depends on the vendor's reputation and the customer's filters. Changing only Reply-To while leaving an unauthenticated custom From address does not solve the problem.

4. Where to check your billing tool

Square Invoices

In Square Dashboard, open Orders & payments (or Invoices & Payments or Payments) → Invoices. Check the customer's contact details and the invoice's Communication options. Email, text message and a manually shared link are different delivery methods.

Inspect a received invoice's actual From address before making DNS changes. If it uses a Square-owned domain, editing your business domain's SPF will not change authentication for that domain. Square's invoice instructions do not provide a universal custom-domain SPF/DKIM recipe.

For an urgent invoice, Square documents a share-link option you can send through an agreed channel. Reference: Square's create-and-send instructions and invoice troubleshooting.

QuickBooks Online

QuickBooks' default invoice sender can be [email protected], rather than your business domain. Check the received message to confirm your route; a connected mailbox or another QuickBooks product may work differently. Intuit's delivery help documents that default sender.

For QuickBooks Online, open Settings → Account and settings → Company → Contact info and review your company email address. Intuit recommends clearing and re-entering it if customers cannot find your messages, then sending a test transaction. Also have the customer check junk or spam.

Reference: Intuit's US troubleshooting instructions. Its mail-server allowlist guidance is not a list of SPF records to paste into your DNS. For mail sent from an Intuit domain, investigate that message with the vendor or the recipient's IT team.

Invoice Ninja

Open Settings → Email Settings and check Email Provider, From Email and Reply-To. The options depend on hosted versus self-hosted use. On the hosted service, Default uses Invoice Ninja's mail service; on a self-hosted install, Default uses the server's mail configuration.

If you use a connected Gmail or Microsoft account, verify that account's domain authentication. If you selected SMTP, Postmark, Mailgun or another provider, authenticate your domain with that provider. Use Send Test Email for SMTP, then test an actual invoice too.

References: Invoice Ninja's Email Settings reference and hosted mail options. Hosted Gmail/Microsoft connections are documented for Pro and Enterprise plans. Use the sending options available in your current account.

Other billing tools

Use the same check: actual From address, selected mail provider, custom-domain verification and a received test. If the tool offers neither domain authentication nor a connected mailbox, use its vendor-domain sending option where available. Do not keep an unsupported custom From address.

5. Test the invoice and investigate other causes

After changes, send an invoice through the route customers actually use. Check SPF, DKIM and DMARC in the received message, then confirm with an affected customer whether a new invoice arrives. Test reminders separately if they use another route. A “sent” status alone does not prove inbox placement.

If authentication passes, compare a simple invoice message with your normal template. Check payment links, shortened URLs and unnecessary attachments. A new domain or poor domain/IP reputation, including a blocklist entry, can still affect delivery. The customer's IT team can review the filtering reason for a specific message. References: Microsoft's filtering FAQ and delivery troubleshooting.

For a payment due now, agree an alternative delivery method with the customer, such as the tool's invoice link through a known contact channel. Avoid repeated resends while you investigate.