Title: SignEmail SMTP & DNS Diagnostic Author: smtpdkim Published: April 25, 2026 Last modified: April 25, 2026 --- Search plugins ![](https://ps.w.org/signemail-smtp-dns-diagnostic/assets/banner-772x250.png?rev =3515405) ![](https://ps.w.org/signemail-smtp-dns-diagnostic/assets/icon-128x128.png?rev=3515405) # SignEmail SMTP & DNS Diagnostic By [smtpdkim](https://profiles.wordpress.org/smtpdkim/) [Download](https://downloads.wordpress.org/plugin/signemail-smtp-dns-diagnostic.2.4.37.zip) * [Details](https://en-ca.wordpress.org/plugins/signemail-smtp-dns-diagnostic/#description) * [Reviews](https://en-ca.wordpress.org/plugins/signemail-smtp-dns-diagnostic/#reviews) * [Installation](https://en-ca.wordpress.org/plugins/signemail-smtp-dns-diagnostic/#installation) * [Development](https://en-ca.wordpress.org/plugins/signemail-smtp-dns-diagnostic/#developers) [Support](https://wordpress.org/support/plugin/signemail-smtp-dns-diagnostic/) ## Description 🚨 Are your WordPress emails going to spam? Without proper email authentication, services like Gmail, Outlook, and Yahoo may block or mark your emails as spam. This results in lost notifications, password resets, and order emails. SignEmail SMTP helps you send reliable WordPress emails using professional SMTP servers, with optional DKIM authentication support. #### Why email authentication matters Modern email providers require proper authentication (SPF, DKIM, DMARC) to trust your messages. Without it, even valid emails may be filtered as spam. #### 📬 SMTP Email Delivery Send all WordPress emails through reliable SMTP servers instead of PHP mail(), improving deliverability and consistency. #### ⚙️ Universal SMTP Compatibility Compatible with Gmail, Outlook, Brevo, cPanel, OVH, Infomaniak, SiteGround, GoDaddy, Bluehost, WP Engine, Kinsta, Namecheap, Gandi, o2switch, LWS, and more. #### 🔍 Email Testing Tool Send test emails to verify inbox delivery and diagnose spam placement in real conditions. #### 🔎 DNS Diagnostic Tool Check SPF, DKIM, and DMARC records using Cloudflare DNS-over-HTTPS. #### 🔒 Secure Storage SMTP credentials are encrypted using AES-256-CBC and stored securely in your WordPress database. #### 🌐 Multilingual Support Full French and English interface with per-user language selection. #### SMTP Features * Full SMTP configuration (SSL / TLS / STARTTLS / None) * Encrypted password storage (AES-256-CBC) * Force sender email and name * Debug logging system * Built-in email test tool * DNS verification (SPF / DKIM / DMARC) * Compatible with WooCommerce, CF7, Elementor, Gravity Forms, BuddyPress, LearnDash, etc. * Fully intercepts wp_mail() #### Optional DKIM Support DKIM email signing is available in the **Premium version** of this plugin — smtp- dkim.com. * Works alongside SMTP delivery * Improves inbox trust and deliverability #### Security & Privacy * SMTP credentials encrypted before storage * No credentials are sent to external servers * License verification (if used) only transmits license key + domain name * No email content is ever transmitted externally ### External Services This plugin connects to the following external services: #### 1. Cloudflare DNS-over-HTTPS Used by the DNS Diagnostic tool to check SPF, DKIM, and DMARC records. * Service: Cloudflare DNS-over-HTTPS API * Endpoint: https://cloudflare-dns.com/dns-query * Data sent: Domain name and DKIM selector (no personal data) * When: Only when the admin manually runs the DNS diagnostic tool * Terms of Service: https://www.cloudflare.com/terms/ * Privacy Policy: https://www.cloudflare.com/privacypolicy/ #### 2. User-configured SMTP server Used to deliver WordPress emails via the SMTP protocol. * Service: Any SMTP server configured by the site administrator (e.g. Gmail, Outlook, Brevo, cPanel) * Data sent: Email content as configured by WordPress (wp_mail) * When: Every time WordPress sends an email * Terms of Service and Privacy Policy: Refer to your SMTP provider #### 3. smtp-dkim.com — License validation (Premium version only) The Premium version validates the license key to enable DKIM signing. * Endpoint: https://smtp-dkim.com/wp-json/sdlm/v1/validate * Data sent: License key + domain name only — no email content, no SMTP credentials * When: On plugin activation and periodically in the background * Terms of Service: https://smtp-dkim.com/politique-de-confidentialite/ * Privacy Policy: https://smtp-dkim.com/politique-de-confidentialite/ Note: The free version available on WordPress.org does not include license validation or DKIM signing. ## Screenshots [[ [[ [[ ## Installation 1. Upload plugin folder to /wp-content/plugins/ 2. Activate plugin 3. Open SignEmail SMTP menu in WordPress admin 4. Configure SMTP settings 5. Run email test 6. (Optional) Configure DKIM if supported by your mail provider 7. Run DNS diagnostic tool ## FAQ ### Does the plugin work without DKIM? Yes. SMTP email delivery works fully without DKIM. ### Is any data sent to external servers? No SMTP credentials or email content are ever sent externally. ### Can I test email delivery? Yes, built-in test tool allows sending emails to verify inbox or spam placement. ### Is it compatible with WooCommerce? Yes, it integrates with all WordPress email systems using wp_mail(). ### Can I move configuration between sites? Yes, settings can be exported and reused. ## Reviews There are no reviews for this plugin. ## Contributors & Developers “SignEmail SMTP & DNS Diagnostic” is open source software. The following people have contributed to this plugin. Contributors * [ smtpdkim ](https://profiles.wordpress.org/smtpdkim/) [Translate “SignEmail SMTP & DNS Diagnostic” into your language.](https://translate.wordpress.org/projects/wp-plugins/signemail-smtp-dns-diagnostic) ### Interested in development? [Browse the code](https://plugins.trac.wordpress.org/browser/signemail-smtp-dns-diagnostic/), check out the [SVN repository](https://plugins.svn.wordpress.org/signemail-smtp-dns-diagnostic/), or subscribe to the [development log](https://plugins.trac.wordpress.org/log/signemail-smtp-dns-diagnostic/) by [RSS](https://plugins.trac.wordpress.org/log/signemail-smtp-dns-diagnostic/?limit=100&mode=stop_on_copy&format=rss). ## Changelog #### 2.4.37 – April 23, 2026 * Improved compatibility with WordPress.org plugin guidelines * Configuration summary card now shows DKIM section status consistently * External test email section: description text simplified and always visible #### 2.4.36 – April 23, 2026 * SMTP debug log now stored in wp-content/uploads/ with .htaccess and index.php protection * External Services section expanded with Cloudflare Terms of Service and Privacy Policy links * Removed deactivation feedback form #### 2.4.35 – April 21, 2026 * Updated language strings to neutral terminology * Removed redundant UI notices from settings page * Fixed SMTP debug log button flickering during live email test polling * Moved all CSS and JavaScript to properly enqueued external files #### 2.4.30 – April 19, 2026 * Improved live SMTP debug log writing during email send * Minor UI improvements to settings page fields #### 2.4.20 – April 13, 2026 * DNS diagnostic improvements and card layout fixes * Configuration summary card moved to top of settings page #### 2.3.9 – April 6, 2026 * Added external email test tool * UX improvements for DNS setup guidance #### 2.3.0 – April 2, 2026 * WordPress 6.9 compatibility confirmed * General stability improvements #### 2.2.0 – March 28, 2026 * Auto-update support added * General improvements #### 2.0.0 – March 3, 2026 * Major refactor of internal architecture * General stability improvements #### 1.0.0 – March 1, 2026 * Initial release ## Meta * Version **2.4.37** * Last updated: **5 months ago** * Active installations: **Fewer than 10** * WordPress Version: ** 5.8 or higher ** * Tested up to: **6.9.10** * PHP Version: ** 8.0 or higher ** * Language * [English (US)](https://wordpress.org/plugins/signemail-smtp-dns-diagnostic/) * Tags: * [deliverability](https://en-ca.wordpress.org/plugins/tags/deliverability/)[DKIM](https://en-ca.wordpress.org/plugins/tags/dkim/) [email](https://en-ca.wordpress.org/plugins/tags/email/)[mail](https://en-ca.wordpress.org/plugins/tags/mail/) [smtp](https://en-ca.wordpress.org/plugins/tags/smtp/) * [Advanced View](https://en-ca.wordpress.org/plugins/signemail-smtp-dns-diagnostic/advanced/) ## Ratings No reviews have been submitted yet. [Your review](https://wordpress.org/support/plugin/signemail-smtp-dns-diagnostic/reviews/#new-post) [See all reviews](https://wordpress.org/support/plugin/signemail-smtp-dns-diagnostic/reviews/) ## Contributors * [ smtpdkim ](https://profiles.wordpress.org/smtpdkim/) ## Support Got something to say? Need help? [View support forum](https://wordpress.org/support/plugin/signemail-smtp-dns-diagnostic/)