My site has a very low amount of email traffic, so the non-sending of mails was not noticed until today. The last successfully sent message was on June 7, with Postman 1.6.14, since than the site was updated to Postman 1.6.17
The server is configured with a self-signed certificate. connections must use STARTTLS on port 587. The email server configurations and software are unchanged.
All emails have failed with the status Unable to connect via TLS.
Examining the email transcript shows that STARTTLS is the last command issued. Other email clients continue to send and receive email using STARTTLS with this server.
I have included the diagnostic test, and an example of the connection logs from the server. Any assistance to restore this back to it's previous working configuration would be appreciated, as it seems this upgrade has been a particularly frustrating regression.
Diagnostic Test:
OS: Linux www 3.16.0-4-amd64 #1 SMP Debian 3.16.7-ckt11-1 (2015-05-24) x86_64
HTTP User Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/43.0.2357.81 Safari/537.36
Platform: PHP Linux 5.6.9-0+deb8u1 / WordPress 4.2.2 en_US
PHP Dependencies: iconv=Yes, spl_autoload=Yes, openssl=Yes, sockets=Yes, allow_url_fopen=Yes, mcrypt=No
WordPress Plugins: WP Missed Schedule, Akismet, BackupBuddy, Customizer Theme Resizer, Easy Pricing Tables Premium, Google Analytics by Yoast, Grid Columns, Groups WooCommerce, Groups, Jetpack by WordPress.com, NinjaFirewall (WP edition), Omega Legacy, P3 (Plugin Performance Profiler), Postman SMTP, Regenerate Thumbnails, Remove Dashboard Access, WPML Multilingual CMS, TablePress Extension: Responsive Tables, TablePress, Theme Check, W3 Total Cache, WC Cancel Order, Wombat English - CDN Offload Plugin, Wombat English Functionality Plugin, Woo Commmerce Addon for WP Courseware, WooCommerce - Autocomplete Order, WooCommerce Cart Reports, WooCommerce Chained Products, WooCommerce Checkout Manager, WooCommerce Composite Products, WooCommerce Cost of Goods, WooCommerce Customer/Order CSV Export, WooCommerce Customer/Order CSV Import Suite, WooCommerce Print Invoice & Delivery Note, WooCommerce Empty Cart Button, WooCommerce For Japan Wombat English Fork, WooCommerce Force Sells, WooCommerce Multilingual, WooCommerce POS Pro, WooCommerce POS, WooCommerce Product Bundles, WooCommerce Sequential Order Numbers Pro, WooCommerce, Wordfence Security, WordPress SEO, WP Courseware, WP Crontrol, WP Multibyte Patch, WP-Optimize, WPAchievements, Clef, WPFront User Role Editor, WPML CMS Nav, WPML Media, WPML String Translation, WPML Translation Analytics, WPML Translation Management, WPML XLIFF, Local SEO for WordPress SEO by Yoast
WordPress Theme: Wombat English - Church
Postman Version: 1.6.17
Postman Sender Domain: wombatenglish.com
Postman Transport URI|Force Email|Name: smtp:tls:plain://mail.wombatenglish.com:587|Yes|Yes
Postman Transport Status (Configured|Ready|Connected): Yes|Yes|Yes
Postman Deliveries (Success|Fail): 25|19
Postman Bind (Success|Fail|Path): Yes|No|/srv/www.wombatenglish.com/wp-content/plugins/postman-smtp/Postman/PostmanWpMailBinder.php
Postman TCP Timeout (Connection|Read): 10|60
Postman Email Log (Enabled|Limit|Transcript Size): Yes|100|128
Postman Run Mode: production
Postman PHP LogLevel: 40000
Postman Stealth Mode: No
Postman File Locking (Enabled|Temp Dir): No | /tmpServer Connection Log:
Jun 10 06:09:48 mail postfix/smtpd[2064]: SSL_accept error from www.wombatenglish.com[104.207.150.207]: 0
Jun 10 06:09:48 mail postfix/smtpd[2064]: warning: TLS library problem: error:14094418:SSL routines:SSL3_READ_BYTES:tlsv1 alert unknown ca:s3_pkt.c:1294:SSL alert number 48:
Jun 10 06:09:48 mail postfix/smtpd[2064]: lost connection after STARTTLS from www.wombatenglish.com[104.207.150.207]
Jun 10 06:09:48 mail postfix/smtpd[2064]: disconnect from www.wombatenglish.com[104.207.150.207]