Thanks @smakazmi15, here you go. I doubt it’s a plugin conflict, but just to point out, the domain of the site is different to the email sending domain, in case that matters.
Mailer: phpmailer
HostName: example.org
cURL Version: 7.81.0
OpenSSL Version: OpenSSL/3.0.2
OS: Linux localhost 5.15.0-76-generic #83-Ubuntu SMP Thu Jun 15 19:16:32 UTC 2023 x86_64
PHP: Linux 8.1.23 C.UTF-8
PHP Dependencies: iconv=Yes, spl_autoload=Yes, openssl=Yes, sockets=Yes, allow_url_fopen=Yes, mcrypt=No, zlib_encode=Yes
WordPress: 6.3.1 en_GB UTF-8
WordPress Theme: SMN
WordPress Plugins: PDF Embedder Premium, Admin Menu Editor, Amazon Link Engine, AWeber for WordPress, BuddyBoss Platform Pro, BuddyBoss Platform, Category Editor, Classic Editor, Vimeotheque, Complianz Privacy Suite (GDPR/CCPA) premium, Complianz - Terms and Conditions, Disable Comments, Divi Builder, Enable Media Replace, Enhanced Media Library, OMGF, LH Add Media from URL, MEC Advanced Speaker, MemberPress AWeber, MemberPress + BuddyPress Integration, MemberPress Divi Content Protection, MemberPress Downloads, MemberPress PDF Invoice, MemberPress Plus 10 (Legacy), Members, Modern Events Calendar, NinjaFirewall (WP Edition), Pages with category and tag, Popups for Divi, Post SMTP, Post Type Switcher, Fixed Widget, Recencio Book Reviews, Rank Math SEO PRO, Rank Math SEO, SMN Book Review Importer, SMN, SupportCandy, Vimeotheque PRO, WebP Express, WPForms AWeber, WPForms Conversational Forms, WPForms Form Locker, WPForms Geolocation, WPForms Google Sheets, WPForms PayPal Standard, WPForms Stripe Pro, WPForms, SupportCandy - Agentgroup, SupportCandy - Assign Agent Rules, SupportCandy - Canned Reply, SupportCandy - Email Piping, SupportCandy - Export Ticket, SupportCandy - Print Tickets, WPvivid Backup Plugin, YouTube Showcase Professional
WordPress wp_mail Owner: /var/www/example.org/wp-includes/pluggable.php
WordPress wp_mail Filter(s): wp_staticize_emoji_for_email, PostsmtpMailer->get_mail_args
Postman: 2.5.9.4
Postman Sender Domain (Envelope|Message): example.net | example.net
Postman Prevent Message Sender Override (Email|Name): No | No
Postman Active Transport: Gmail API (https:oauth2://www.googleapis.com:443)
Postman Active Transport Status (Ready|Connected): Yes | Yes
Postman Deliveries (Success|Fail): 113511 | 572
Postman Email Log (Enabled|Limit|Transcript Size): Yes | 10000 | 128
Postman PHP LogLevel: 30000
Postman Stealth Mode: Yes
