StackMime Mail documentation

1. Download the zip from the product page, or search for “StackMime Mail” under Plugins → Add New once it is listed on WordPress.org.
2. For the zip, go to Plugins → Add New → Upload Plugin, choose the file, install and activate.
3. Open Settings → StackMime Mail.

1. Sign in at myaccount.google.com and open Security.
2. Turn on 2-Step Verification.
3. Search for App passwords and create one called “Website”.
4. In StackMime Mail, choose Gmail, enter your Gmail address and paste the 16-letter code. Spaces don’t matter.
5. Click Save settings, then send a test.

No Google Cloud project or OAuth app is needed.

Choose SMTP service and pick your provider: the server, port and encryption fill in for you. Presets cover Microsoft 365 / Outlook, Zoho Mail, Brevo, SendGrid, Mailgun, Amazon SES, Postmark, Yahoo, iCloud, Hostinger and GoDaddy. For anything else, choose a custom server.

Use the username and password (or API key) your service gives you. For most services the username is the full email address.

Passwords saved in the settings are encrypted with your site’s own secret keys (libsodium) and never shown again. If you’d rather not store it in the database at all, add this line to wp-config.php, above “That’s all, stop editing!”:

define( 'STACKMIME_MAIL_PASSWORD', 'your-password-or-app-password' );

Open Send a test and send yourself a plain-text or HTML email. If it fails, the screen explains what to change: a wrong password, a blocked port or the spam folder.

Every email is listed with its date, recipients, subject, status and any error, with filters, search and paging. Message contents are never stored. Rows are deleted after the number of days you choose (30 by default, up to 90), and Empty log clears it at once.

If an email fails, admins see a dashboard notice with the exact error and a link to the log.

Set the From name and a From address on your own domain, for example hello@yourdomain.com. Add a default Reply-To, choose whether to force these over other plugins, and set the Return-Path for better SPF alignment.

“Could not authenticate”

The username or password is wrong. Gmail, Yahoo and iCloud need an app password, not your normal password.

“Could not connect to SMTP host”

Check the server name and try the other port: 587 with TLS, or 465 with SSL. Some hosts block outgoing mail ports; ask your host to open one.

Sent, but in spam

Send from an address on your own domain and add the SPF and DKIM records your mail service gives you to your DNS.

StackMime Mail connects only to the SMTP server you choose, so your emails can be delivered. Nothing is sent until you choose a service and save, and nothing is sent to StackMIME. Each email, and the username and password you entered, go to that server when WordPress sends mail or you send a test. With Gmail, that is smtp.gmail.com, under Google’s terms and privacy policy.

1.1.1

• New: a Getting started guide and a one-time welcome notice after a fresh install (no redirect).

1.1.0

• New: a cleaner settings screen with a status summary and 7-day totals.
• New: SMTP presets for popular services.
• New: default Reply-To and Return-Path.
• New: HTML or plain-text test emails, with troubleshooting tips.
• New: log filters, search, paging and an Empty log button.

1.0.1

• A password saved for one service is never sent to another after switching services.

1.0.0

• First release.