Hi partha.rkl,
I had a similar thing. What I did was first installing a mail log plugin to see what the headers contained (like https://wordpress.org/plugins/wp-mail-logging/ ).
Then I forced the FROM to always be what was set by WP-mail-SMTP in my own plugin using the below code.
That seems to have solved for me.
Pascal.
/**
* Since the install of WP-Mail-SMTP we need to make sure the FROM is the same as the one specified in the plugin
* These filters will overwrite any FROM send by other plugins.
*/
add_filter('wp_mail_from','custom_wp_mail_from');
function custom_wp_mail_from($email) {
return get_option('mail_from');
}
add_filter('wp_mail_from_name','custom_wp_mail_from_name');
function custom_wp_mail_from_name($name) {
return get_option('mail_from_name');
}