Editor’s note: disabling SSL verification has security implications. Without verification of the authenticity of SSL/HTTPS connections, a malicious attacker can impersonate a trusted endpoint such as Gmail, and you’ll be vulnerable to a Man-in-the-Middle Attack.
Be sure you fully understand the security issues before using this as a solution.
You can add below code in /config/mail.php ( tested and worked on laravel 5.1, 5.2, 5.4 )
'stream' => [
'ssl' => [
'allow_self_signed' => true,
'verify_peer' => false,
'verify_peer_name' => false,
],
],