Hello, I can also confirm this. The automated update that occurred on 2020-11-25 caused the following error to come up in my installation, breaking any email functionality:
[02-Dec-2020 06:00:11 UTC] PHP Fatal error: Uncaught Exception: The message is not valid because it contains no message or html field. in /home/username/public_html/wp-content/plugins/wp-mail-logging/src/WPML_MailExtractor.php:37
Stack trace:
#0 /home/username/public_html/wp-content/plugins/wp-mail-logging/src/WPML_MailExtractor.php(19): No3x\WPML\WPML_MailExtractor->extractMessage(false)
#1 /home/username/public_html/wp-content/plugins/wp-mail-logging/src/WPML_Plugin.php(214): No3x\WPML\WPML_MailExtractor->extract(false)
#2 /home/username/public_html/wp-includes/class-wp-hook.php(287): No3x\WPML\WPML_Plugin->log_email(false)
#3 /home/username/public_html/wp-includes/plugin.php(206): WP_Hook->apply_filters(false, Array)
#4 /home/username/public_html/wp-includes/pluggable.php(182): apply_filters('wp_mail', Array)
#5 /home/username/public_html/wp-content/plugins/wp-mail-smtp/src/Admin/Pages/TestTab.php(172): wp_mail('[email protected]', 'WP Mail SMTP: H...', '\t\t<!doctype htm...', Array)
#6 /home/username/public_html/wp-content/plugins/wp-mail-smtp/src/Admin in /home/username/public_html/wp-content/plugins/wp-mail-logging/src/WPML_MailExtractor.php on line 37
It seems to be interfering with the latest version of “WP Mail Logging by MailPoet” plugin. Disabling either plugin prevents the error from happening and allows the emails to be sent successfully, however the logging functionality is important for me, so I have disabled the “Check & Log Email” plugin until this gets fixed.