@yuniar
Figured it out. Please consider updating the code in reset_password.php
In reset_password.php line 86: $s_transport->setEncryption('tls');
However, in your includes/helper-functions.php, there is dialogue specifying differences between 465=ssl and 587=tls.
In my situation, all 'regular notification' emails would send successfully because your software would tell swiftmailer to differ between 465ssl and 587tls.
However, when a password was being reset, such logic was not in place. This caused the function in my environment to fail. Please consider putting that logic (port 465ssl vs 587tls) into any new versions.
Thank you,
Patrick Hait