Yes, but “Outlook” covers two very different products, and the answer depends on which one you mean. A personal Outlook.com account (the free consumer mailbox at @outlook.com, @hotmail.com, @live.com) works as an SMTP relay for a low-volume WordPress site. A Microsoft 365 business account works too, and is the correct route for any site sending mail from a custom domain, but requires OAuth rather than password auth and hits a daily recipient cap that transactional providers do not.
Personal Outlook.com is fine for a personal blog or a hobby site. Microsoft 365 is fine for a small business site whose sending volume stays inside Microsoft’s per-mailbox limits. Neither is the right choice for WooCommerce, a membership site, or anything else that needs to send transactional mail at meaningful volume.
Personal Outlook.com (free consumer accounts)
SMTP host: smtp-mail.outlook.com
Port: 587
Encryption: STARTTLS
Authentication: Your Outlook.com email address and password. If two-factor auth is enabled on the account, generate an 
app password at account.microsoft.com and use that instead of the account password.
Any mailer plugin with SMTP support handles this: WP Mail SMTP, FluentSMTP, and Post SMTP all work identically. Pick “Other SMTP”, enter the host and port above, paste the credentials, done.
The catch is authentication alignment. Mail sent through a personal Outlook.com account is DKIM-signed as outlook.com, not as your WordPress site’s domain. That means the DKIM key you publish on your own DNS is not the one signing the mail, and DMARC alignment will fail on any site that enforces it. For a personal blog where the sender is expected to be [email protected], that is fine. For a site that wants mail to look like it came from [email protected], this route is wrong: use a transactional email provider instead. See transactional email providers for the alternatives.
Microsoft 365 business accounts
SMTP host: smtp.office365.com
Port: 587
Encryption: STARTTLS
Authentication: OAuth 2.0 (as of March 2025, when Microsoft completed the basic-authentication cutoff for SMTP AUTH). Basic auth with username and password is no longer accepted.
The mailer plugin has to support the OAuth flow. WP Mail SMTP handles Microsoft 365 OAuth on its Pro tier. FluentSMTP handles it on the free tier. Post SMTP handles it on the free tier. Configuring the OAuth flow requires registering an app in Microsoft’s Entra ID (Azure AD) portal; the plugin’s documentation walks the specific fields. See the Microsoft 365 review for the entity overview and the WordPress SMTP with Microsoft 365 guide for the full setup.
Microsoft 365 mailboxes are DKIM-signed against your custom domain (assuming you have Microsoft 365 configured to send as @yourdomain.com), so alignment works. The failure mode here is not authentication but capacity: a Microsoft 365 mailbox is limited to 10,000 recipients per day at a rate of 30 messages per minute. That ceiling covers a small business site sending admin alerts and password resets. It does not cover a WooCommerce store on Black Friday.
Neither is the right tool for high-volume transactional mail
The pattern of using a human mailbox (personal Outlook.com, Microsoft 365, Google Workspace, or otherwise) as the relay for a WordPress site’s outbound mail works technically and fails at scale. Two failure modes recur:
- Rate limits. Personal Outlook.com throttles messages after a few hundred a day. Microsoft 365 caps at 10,000. A busy site hits these limits and the SMTP connection starts returning throttling errors instead of accepting messages.
- Mixed content. The same mailbox is now handling both the human’s inbox mail and the site’s transactional mail. Bounces from a bad WordPress recipient list end up in the same reputation bucket as the human’s normal correspondence, and a mail-service reputation problem on the site starts affecting the human’s ability to send email.
For any WordPress site sending more than a few hundred messages a month, a transactional provider (Postmark, SMTP2GO, Amazon SES, Brevo) is the correct route. See What is the best way to set up email on WordPress? for the setup that scales.