Yes, I have. This error has been there since as long as I’ve used Post SMTP, which is maybe 2 years now… It’s just it never affected anything so I didn’t care to report it.
But, I was on the forum and so took the time.
If you want to see it, try using the Query Monitor plugin. It will show when youg get on the wizard page.
As for the diagnostics, it is below. I removed some things.
Mailer: postsmtp
HostName: [removed]
cURL Version: 7.58.0
OpenSSL Version: OpenSSL/1.1.1i
OS: [removed]
PHP: Linux 7.4.14 en_US.UTF-8
PHP Dependencies: iconv=Yes, spl_autoload=Yes, openssl=Yes, sockets=Yes, allow_url_fopen=Yes, mcrypt=No, zlib_encode=Yes
WordPress: 5.6 en_US UTF-8
WordPress Theme: Pro – Child Theme
WordPress Plugins: Query Monitor, WP Missed Schedule (The Original), ACF to REST API, Ad Inserter, Advanced Cron Manager, Advanced Custom Fields PRO, Akismet Anti-Spam, Cloudflare, Custom Post Type UI, GAinWP Google Analytics Integration for WordPress, Social Login, Post SMTP, Advanced Editor Tools (previously TinyMCE Advanced), User Menus, User Role Editor, WooCommerce PayPal Checkout Gateway, WooCommerce Stripe Gateway, WooCommerce Memberships, WooCommerce Subscriptions, WooCommerce, WP Content Filter, WP Rocket
WordPress wp_mail Owner: [removed]/wp-content/plugins/post-smtp/Postman/PostmanWpMailBinder.php
WordPress wp_mail Filter(s): wp_staticize_emoji_for_email, PostsmtpMailer->get_mail_args
WordPress phpmailer_init Action(s): PostsmtpMailer->phpmailer_smtp_init
Postman: 2.0.19
Postman Sender Domain (Envelope|Message): [removed]
Postman Prevent Message Sender Override (Email|Name): Yes | Yes
Postman Active Transport: SMTP (smtp:tls:oauth2://smtp.gmail.com:587)
Postman Active Transport Status (Ready|Connected): Yes | Yes
Postman Deliveries (Success|Fail): 127282 | 1664