Support for Drupal 7 is ending on 5 January 2025—it’s time to migrate to Drupal 10! Learn about the many benefits of Drupal 10 and find migration tools in our resource center.
The function drupal_mail_wrapper references "$mailkey", but $mailkey doesn't seem to be defined.
I think the following line fixes it:
$mailkey = $message['id'];
Comments
Comment #1
timtrinidad CreditAttribution: timtrinidad commentedDuplicate of #965150: mailkey exclusion does not work at all