Quick answer
QuickBooks email not sending almost always traces to a sign-in problem, not a broken internet connection. In QuickBooks Desktop, re-authenticate Webmail or toggle the Send Forms preference to reload Outlook. In QuickBooks Online, clear and re-enter the company email address, then check the customer's spam folder. Send a test email to yourself before changing anything else.
What "QuickBooks email not sending" actually means
This problem covers two products that share nothing under the hood. QuickBooks Desktop hands your invoice to the mail engine configured on your own PC, either Webmail or Outlook. QuickBooks Online sends from an Intuit mail server, so a message can leave QuickBooks successfully and still be rejected on the recipient's side. Diagnose the platform first; the fixes do not overlap.
| Platform | Typical failure | Start with |
|---|---|---|
| QuickBooks Desktop (Windows) | Expired Webmail sign-in, Outlook conflict, security software blocking ports 465 or 587 | Step 2 |
| QuickBooks Desktop for Mac | Default mail app unavailable, or the Intuit account authorization expired | Step 6 |
| QuickBooks Online | Company email address has a typo or hidden space, or the recipient's server flags Intuit mail | Step 7 |
Symptoms that identify the cause
- Desktop, Webmail: a dialog reports an incorrect password, an unable-to-connect message, or that the antivirus blocked outgoing emails. The invoice stays open and is not queued for retry.
- Desktop, Outlook: QuickBooks displays "QuickBooks is unable to send your email to Outlook" or "Outlook cannot log on," even though Outlook sends on its own.
- Mixed recipients: the send fails with a network connection error when several addresses sit in the To field.
- Online: the transaction shows email sent but the customer never receives it, and the activity log shows Sent without ever showing Viewed.
- Attachments: the email arrives but the PDF is missing or blank, which points at PDF generation rather than mail delivery.
Common causes, ranked
- An expired mail sign-in. Gmail and Yahoo now require an app password for desktop mail clients, and Google retired the old "less secure apps" switch. The stored password stops working with no change on your side.
- The Send Forms preference points at the wrong engine. If QuickBooks is set to Outlook but you use Webmail, every send fails.
- QuickBooks running as administrator while Outlook does not. Windows MAPI cannot pass the message between processes at different privilege levels.
- Security software blocking outgoing mail. Antivirus email scanning and firewall rules interrupt connections to port 465 for Yahoo or 587 for most providers.
- A damaged MAPI32.dll. Outlook still works alone but ignores QuickBooks requests once these Windows messaging components break.
- A bad address in QuickBooks Online. One stray leading or trailing space in the company email field breaks delivery for every form.
- Recipient-side filtering. Messages from QuickBooks Online originate from Intuit mail servers, which strict corporate filters quarantine.
Before you begin
- Confirm the platform and version. Press F2 in QuickBooks Desktop; in QuickBooks Online, open Settings and check the subscription.
- Set aside 20 to 30 minutes for Desktop fixes; the Outlook and MAPI steps are slowest.
- Have a second email address on a different domain ready for delivery testing.
- Know your provider's server settings. QuickBooks Desktop supports SSL connections but not providers that require starttls.
How to fix QuickBooks Desktop email delivery
Send a test email and read the exact error
Open an invoice, select the email icon, and send it to yourself. An error about the email server or password points at Webmail. An Outlook-specific message points at the MAPI integration. A message about antivirus blocking outgoing emails points at security software. Sending to yourself first also separates a credential failure on your PC from a spam filter on the recipient's server.
Check the Send Forms preference
Go to Edit → Preferences → Send Forms and open the My Preferences tab. Confirm the selected engine matches the provider you actually use. If you use Exchange or Office 365, sign in to Outlook before changing anything here.
Then force a rebuild: switch to Webmail, select OK, return to the tab, and switch back to Outlook. Close QuickBooks, restart the PC, and test again. This toggle clears many one-off failures.
Re-authenticate Webmail and use an app password
For Webmail, go to Edit → Preferences → Send Forms, select your account under Web Mail, and choose Edit. Re-open the account and complete the provider's sign-in page. Incomplete authorization is the most common silent failure: QuickBooks looks configured but holds no valid token.
For Gmail, create an App Password in Google Account security settings and paste it into the password field; a normal account password is rejected. For Yahoo, generate a third-party app password, and note that a batch-sending Yahoo password expires after 12 invoices or transactions. Confirm the server and port: 465 for Yahoo, 587 for Gmail and most others, with SSL enabled.
Back up before you touch system components. The next two steps modify Windows messaging files and QuickBooks configuration. Create a System Restore point first, close Outlook, Word and QuickBooks, and keep your mail password handy in case you need to recreate the Outlook profile.
Repair the Outlook connection
Find QuickBooks.exe in the program folder, right-click it, choose Properties → Compatibility, and clear Run this program as Administrator. On newer versions this alone fixes the Outlook error.
Next, split-test the problem. In Word, use File → Share → Email as PDF Attachment. If Word cannot send either, the fault is in Outlook or Office and Microsoft support is the right path. If Word sends but QuickBooks does not, run C:\Windows\System32\Fixmapi.exe, restart the PC, and test again.
Allow QuickBooks through security software
In your antivirus or endpoint console, add QBW32.exe, QBDBMGRN.exe, and QBDBMGR.exe from C:\Program Files\Intuit\QuickBooks [year]\ to the allowed-apps list, and allow outgoing traffic on ports 465 and 587. Do not switch protection off entirely.
If the error says the antivirus blocked outgoing emails, QuickBooks Support documents one extra switch: press F2 then F3 in QuickBooks, open Tech Help → Open File, select QBW.ini, and add [QBWEBMAIL]CUSTOM_CERT_ENABLE=1 at the bottom. Save, close Notepad, and restart QuickBooks.
QuickBooks Desktop for Mac: check the email preference
On Mac, open the QuickBooks menu, select Preferences, then the Email icon, and review the For sending Emails section. Choose Send using your Default Email handling application or Send directly out of QuickBooks using your Email Account, and re-authorize the account if validation fails.
If you use the default option, test from Mail itself; QuickBooks cannot send when the default mail app is signed out. Other quirks are covered in QuickBooks Mac troubleshooting.
How to fix QuickBooks Online email delivery
Verify the addresses and check the spam folder
Go to Settings → Account and settings → Company and select Edit in Contact info. Clear the Company email field and retype it, watching for hidden spaces. Confirm the customer's address, then resend the form and ask them to check junk and spam folders.
If the first test fails, send the same form to a different address on a different domain to see whether the block follows your company address or their provider. Ongoing sign-in trouble is covered in fixing QuickBooks Online login loops.
Review bounced emails and allowlist Intuit mail servers
In QuickBooks Online, go to Home and select View the errors under Tasks. The list shows the date, customer, reference number and error for each failed message. If a transaction shows Sent but never Viewed, the message left Intuit and was filtered downstream.
Fix those cases at the server level: ask an IT professional to add the QuickBooks Online mail host names and IP addresses from Intuit's published list to the outgoing mail allow list. QuickBooks Online cannot send from your own domain. As a fallback, save the form as a PDF and send it manually using the steps in QuickBooks PDF problems.
Verify the fix
- Send a test invoice to your own address and confirm it arrives with the PDF attached.
- Send the same invoice to a second domain to rule out a provider-specific block.
- In QuickBooks Desktop, the send completes with no dialog; in QuickBooks Online, the activity log shows Sent and later Viewed.
- For a bulk send, process three invoices and verify all three before releasing the batch.
- Ask one customer to confirm receipt; their filter is the only complete test.
If email still will not send
In QuickBooks Desktop, create a new Windows user account and test email from QuickBooks there. If it works, the original Windows profile or Outlook data file is damaged, and a new Outlook profile restores normal behavior. If you use a hosted desktop such as Rightworks, confirm the provider's multi-factor sign-in has not expired, because hosted sessions require periodic re-authentication. For invoice delivery settings and reminders, see QuickBooks Online invoicing issues.
In QuickBooks Online, try a supported browser in a private window to rule out cached session data, and recheck the customer's address character by character. Repeated bounces on one customer usually mean their mail administrator must allowlist Intuit's sending hosts; no QuickBooks Online setting overrides their filter.
Prevention
- Calendar your Gmail and Yahoo app passwords and replace them before they rotate, especially if you batch-send invoices.
- Keep the QuickBooks program folder in your security software's exclusion list after every major upgrade.
- Use a comma between multiple recipients in Desktop, never semicolons or line breaks.
- Review the QuickBooks Online bounce list monthly to catch delivery failures early.
Frequently asked questions
Why did my Gmail password stop working in QuickBooks Desktop?
Google retired sign-in for desktop mail apps using less secure account access. QuickBooks Desktop now needs a Google App Password tied to an account with two-step verification enabled. Generate one and re-enter it under Edit → Preferences → Send Forms.
Does QuickBooks Online use my email server?
No. QuickBooks Online sends from Intuit's mail servers, and the message is dressed to look like it came from your provider. That is why there are no SMTP settings to configure, and why strict recipient servers sometimes need Intuit's host names and IP addresses on an allow list.
Why does email fail when I add multiple recipients in QuickBooks Desktop?
Desktop parses recipient lists strictly. Separate addresses with a comma and remove semicolons, extra spaces or line breaks. One malformed address in the To field can produce a generic network connection error that has nothing to do with the internet.
Can I send an invoice as a PDF if email will not cooperate?
Yes. In Desktop, use the invoice's email menu to save the form as a PDF, then attach it in your normal mail client. In QuickBooks Online, select Print or Save as PDF. This bypasses the mail integration and gets the document out immediately; if PDF creation itself fails, rebuild the print engine instead.