QuickBooks Desktop emailing invoices with Microsoft 365 (Web Mail or Outlook): email through Microsoft 365 after Basic auth ends

Short answer: QuickBooks Desktop sends through Web Mail or Outlook. Update to the latest release, then either reauthorize Web Mail (Microsoft sign-in, grant Intuit access) or switch to Outlook 2010 or newer with a profile. Outlook doesn't use SMTP AUTH, so the Basic auth switch-off doesn't affect it.

Deadline: Microsoft 365 turns off SMTP AUTH Basic auth by default at the end of December 2026 – dates and background.

Modern authentication (OAuth) support

Intuit's Web Mail setup opens your provider's login page, where you sign in and grant Intuit access; the reauthorize flow ends with Continue and Allow, and Intuit says you don't need to change any default permissions set by Microsoft. Intuit doesn't call this OAuth, and which protocol and Microsoft permissions it uses are not documented. Intuit's provider table lists Microsoft Outlook 365 as outlook.office365.com, port 587, SSL enabled. QuickBooks Community users reported in 2021 that Office 365 Web Mail only worked with Authenticated SMTP turned on, so older setups may still depend on SMTP AUTH. The Outlook option hands the email to Outlook 2010 or newer with an Outlook profile. Outlook doesn't use SMTP AUTH (Microsoft Learn), so the Basic auth switch-off doesn't touch it. Whether the new Outlook for Windows works: not documented by Intuit.

What you will see when it breaks

Best fix

  1. Check the send method: Edit → Preferences → Send Forms → My Preferences shows Web Mail or Outlook. To see whether the QuickBooks mailbox still logs in over SMTP AUTH, run the free SMTP AUTH sender script.
  2. Update QuickBooks Desktop to the latest release. Intuit lists this as the first step before reauthorizing.
  3. Web Mail: Edit → Preferences → Send Forms → Web Mail → Add. Fill in Add Email Info (Intuit's values for Microsoft Outlook 365: outlook.office365.com, port 587, SSL on) and click OK twice. On Microsoft's login page, sign in and grant Intuit access. Intuit says webmail accounts need two-step verification turned on.
  4. If QuickBooks says it can't send due to a network connection failure: open any form, click Email, then Send. Sign in with your Intuit account if asked, click Continue in the Webmail Authorization window, then Allow.
  5. Outlook route: install Outlook 2010 or newer, create an Outlook profile, make Outlook the default email program with a default profile, then choose Outlook under Send Forms. Before QuickBooks Desktop 2024, Click-to-Run Office isn't supported; Intuit says 64-bit Outlook can help when Outlook doesn't appear.
  6. If QuickBooks can't hand the email to Outlook: turn off Run this program as Administrator forQuickBooks.exe, select Outlook again under Send Forms, and if that fails run C:\Windows\System32\Fixmapi.exe.
  7. Hosted QuickBooks (for example Rightworks) may still ask you to sign in to Web Mail each time you send. That is expected, per Intuit.

If it can't do OAuth

  1. Web Mail keeps failing with Microsoft 365? Switch to Outlook: it signs in to Microsoft 365 itself and doesn't depend on SMTP AUTH.
  2. A relay connector is not a documented option: Intuit's Web Mail always signs in to the provider, and a no-login server setting is not documented.
  3. Stopgap only: if your Web Mail setup still logs in with a password, an admin can turn Basic auth for SMTP AUTH back on for now. It ends when Microsoft removes it for good; the date is due in the second half of 2027. See the SMTP AUTH change.
Send methodEdit > Preferences > Send Forms > My Preferences: Web Mail or Outlook
Web Mail, Microsoft (Intuit table)Provider Microsoft Outlook 365, server outlook.office365.com, port 587, SSL enabled
Web Mail sign-inMicrosoft login page, grant Intuit access; reauthorize with Continue, then Allow
OAuth / Microsoft permissionsNot documented by Intuit
Outlook optionOutlook 2010 or newer with an Outlook profile, set as the default email program
Click-to-Run OfficeNot supported before QuickBooks Desktop 2024
New Outlook for WindowsNot documented by Intuit
Relay connector (no-login SMTP)Not documented

Check your domain's SPF and DMARC

A relay sends from your office IP, so it must be in your SPF record.

Several devices to move? The Microsoft 365 SMTP Fix Kit puts every printer, scanner, app and script on one printable guide: decision table, relay connector set-up, per-device steps, a sender worksheet and a checklist.

Get the kit ($19)

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Sources

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