Notification sending error

Hello?@alexeerma ,

We hope this message finds you well.

Thank you for reaching out to our Support team. We are concerned to hear about the issue you’re facing and sincerely regret any inconvenience caused.

The email you received was sent from our server because issues were detected while delivering your email through your configured email service provider.

The error message seems to be due to missing “To email”, as you have pointed out that this happens with the emails send through a particular plugin, could you please share the name of the plugin? Perhaps sharing the Diagnostic test report will allow us to reproduce a similar environment as yours’s and assist you effectively.

Looking forward to your response & an opportunity to assist you.

Warm regards,
Support Team – WP Experts

Hey!
The name of the plugin is registrations for the events calendar.
This is the diganostics test.

Mailer: postsmtp
HostName: etfl.ee
cURL Version: 8.4.0
OpenSSL Version: OpenSSL/1.1.1w
OS: Linux sn-69-30.tll07.zoneas.eu 5.15.138-zoneos #1 SMP Wed Nov 15 10:55:18 -00 2023 x86_64
PHP: Linux 8.3.16 C.UTF-8
PHP Dependencies: iconv=Yes, spl_autoload=Yes, openssl=Yes, sockets=Yes, allow_url_fopen=Yes, mcrypt=No, zlib_encode=Yes
WordPress: 6.7.2 et UTF-8
WordPress Theme: Brandweb Child
WordPress Plugins: Query Monitor, LayerSlider, Advanced Custom Fields Multilingual, Advanced Custom Fields PRO, Algori PDF Viewer Lite, Core Rollback, Duplicator, Email Templates, Embed PDF Viewer, Event Tickets, Grids, WPCode Lite, Koko Analytics, HubSpot All-In-One Marketing - Forms, Popups, Live Chat, Max Mega Menu, Ninja Forms - User Management, Ninja Forms, PDF Block, Post SMTP, Prevent Direct Access, Registrations for The Events Calendar, Search & Replace, Search & Filter Pro, WPML Multilingual CMS, The Events Calendar, Wordfence Security, WordPress Importer, Yoast SEO, WP All Export, WP Fastest Cache, WP Media folder, WP Rollback, WPML SEO, WPForms, WPML Media Translation, WPML String Translation, WPForms Multilingual
WordPress wp_mail Owner: /data01/virt59371/domeenid/www.etfl.ee/htdocs/wp-content/plugins/post-smtp/Postman/PostmanWpMailBinder.php
WordPress wp_mail Filter(s): wp_staticize_emoji_for_email, PostsmtpMailer->get_mail_args, Mailtpl_Mailer->send_email
WordPress wp_mail_from Filter(s): wordfence::fixWPMailFromAddress, Mailtpl_Mailer->set_from_email
WordPress wp_mail_from_name Filter(s): Mailtpl_Mailer->set_from_name
WordPress wp_mail_content_type Filter(s): Mailtpl_Mailer->set_content_type
Postman: 3.1.3
Postman Prevent Message Sender Override (Email|Name): No | No
Postman Active Transport: Default (smtp:none:none://localhost:25)
Postman Active Transport Status (Ready|Connected): No | Yes
Postman Deliveries (Success|Fail): 3191 | 20

Hey @alexeerma

Thank you so much for sharing the requested information. I replicated a similar scenario as yours & especially Registrations for the Events Calendar plugin, but wasn’t able to reproduce it on my end. Kindly ensure that the email settings are correctly configured in the plugin.

Kindly, deactivate all plugins except Post SMTP & revert to basic theme like Twenty-Twenty Five. To see if the issue is due to the conflict with any other plugin.

This will help us narrow down the issue.

Warm regards,
Support Team – WP Experts