[exim] Exim not log from address

Hello Team,

Exim not log from addreess in log file.

Here is my command to send mail via php.

mail($to, "The subject", "The mail body", $header, -f returns@??? );

my log selector setting is
log_selector = +subject +received_recipients +received_sender +sender_on_delivery +smtp_confirmation +deliver_time -retry_defer

In log file i am getting F=<returns@???> insted of actual From: address.

My exim version is 4.80.1-49

Thanks in advance.

Regards,
Dilip Jadav