PHPMailer SMTP test mail working,but password reset emails not reaching mailboxes

Problem/Motivation

PHPMailer SMTP test mail working, but password reset emails not reaching mailboxes

Steps to reproduce

1. Set PHPMailer SMTP with SMTP server information. I used a gmail SMTP Server.
2. Send test emails using PHPMailer SMTP interface
3. Tried 2 emails one of hotmail.com and other of gmail.com
4. Both landed successfully in their respective email boxes.
5. Tried forgot password email for 2 of the users who are having same hotmail and gmail addresses as mentioned in above step
6. No email is reaching the mailbox but Drupal detailed log show successful delivery.

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes