I am getting hundreds of these errors intermittently.
This only happened once I switched over to HHVM, which required PHP5.6 to run. The issue has to do with PHP5's updated SSL interfaces and security requirements. All resources I find on the error suggest that I change settings that look like this.
This is apparently caused by PHP5.6 refusing to talk to the server with its self-signed cert. That needs to stop, immediately. Where can I change these settings in XenForo?
ErrorException: Email to firstname.lastname@example.org failed: stream_socket_enable_crypto(): SSL operation failed with code 1. OpenSSL Error messages: error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed - library/Zend/Mail/Protocol/Smtp.php:206
$mail->SMTPOptions = [ 'ssl' => [ 'verify_peer' => false, 'verify_peer_name' => false, 'allow_self_signed' => true ]];