You send an invoice from QuickBooks. At the next follow-up, the customer says, “I never saw it.” Now the invoice is unpaid, and you do not know whether it was ignored, blocked, or buried in spam.
If your QuickBooks invoices are going to spam, do not abandon email. Use the status QuickBooks gives you, fix the likely problem, and add a second channel when a delayed payment would hurt.
Quick answer: Check whether the invoice says Delivery issue, Sent, or Viewed. Fix delivery errors first. If an important invoice is sent but not viewed, resend it directly and consider mailing a paper copy too.
Start with the QuickBooks invoice status#
QuickBooks gives you useful clues, although it cannot tell you exactly where every message landed.
QuickBooks status | What it tells you | What to do next |
|---|---|---|
Delivery issue | The email did not reach at least one recipient | Check each recipient address, correct any error, and resend |
Sent, not viewed | QuickBooks sent it, but the customer has not opened it | Ask them to check spam, resend from a connected Gmail address or your regular business email, and follow up |
Viewed, unpaid | The customer opened the invoice | Treat this as a payment follow-up, not primarily an email-delivery problem |
“Viewed” is useful, but it is not legal proof of receipt. “Sent” does not prove inbox placement; the message may be in spam, quarantine, or an address the customer rarely checks.
Try these five fixes#
1. Check the customer’s email address#
Compare the address in the customer record with a recent message from that customer. A small typo can look like a larger delivery problem.
2. Check your company email#
Open Settings → Account and settings → Company → Contact info. Clear and re-enter the company email without extra spaces, then send a test invoice.
This is one of Intuit’s recommended fixes.
3. Ask the customer to check spam or quarantine#
Ask the customer to check spam and any separate quarantine report. For security, confirm the invoice through a channel they already recognize before asking them to mark it “not spam.”
4. Resend it from an address they recognize#
If your account offers the option, QuickBooks Online can send from a connected Gmail address.
Otherwise, download the PDF and send it from the business address the customer already knows.
5. Involve the customer’s IT team when the problem repeats#
If several invoices to one company disappear, its mail system may be filtering Intuit. Ask its IT team to use Intuit’s published mail-server details. Most owners should not change DNS records themselves.
What an unseen invoice costs#
The expense is not the email. It is the uncertainty: delayed cash, less reliable forecasts, and extra calls, resends, and reconciliation. Your delivery plan should match the consequence of a miss.
When to add a paper copy#
For an important invoice, use email plus paper, not email versus paper. Email keeps the payment link and speed. Paper gives the customer another way to see the bill.

Situation | Sensible channel plan |
|---|---|
Repeat customer who reliably views and pays | Email |
Delivery issue | Correct the address and resend before changing channels |
Sent but not viewed, and timing matters | Resend directly, contact the customer, and mail a copy if the silence continues |
New customer, prior delivery trouble, or payment critical to cash flow | Send electronically and mail a paper copy from the start |
Contract or law requires evidence | Choose the USPS service that supplies the required record; ordinary First-Class Mail may not be enough |
Set the threshold around business impact, not an arbitrary amount. If a delay would disrupt payroll, purchasing, or a project, one inbox is unnecessary risk.
For broader channel economics, see the mailed-versus-emailed invoice comparison. If the balance is already late, use a clear past-due invoice letter.
Know what the mailing record proves#
Paper is not automatically proof of delivery. Choose the service based on the record you need.
Mailing option | What it gives you | Available through Postmarkr today? |
|---|---|---|
First-Class letter | A second physical channel; no guaranteed tracking or proof of receipt | Yes |
Certificate of Mailing | A USPS-stamped record showing when you mailed the item; no delivery record | No |
Certified Mail | A mailing receipt and, upon request, verification of delivery or attempted delivery | Coming soon |
Postmarkr handles the First-Class backup without the printer or post-office trip. Upload the PDF, add the address, and we print and mail it after an address check.
Your dashboard shows processing milestones, with USPS scan updates when available. Updates may be delayed or missing and are not proof that the customer received the invoice.
Mail an invoice through Postmarkr, or start with the complete guide to invoice printing and mailing.
Most invoices should still go by email. But when an unpaid invoice would materially affect the business, do not leave the entire payment to one message in one inbox.