Php Mail not working

Hello,

OS : centos7
php-fpm with apache
plesk :12.5

I am trying to run a php script to send mail, by using below url.

http://licensing.kanors-emr.org/testemail.php

Getting below error in maillog

Apr 11 16:57:25 plesk journal: plesk sendmail[18355]: handlers_stderr: PASS
Apr 11 16:57:25 plesk journal: plesk sendmail[18355]: PASS during call 'limit-out' handler
Apr 11 16:57:25 plesk journal: plesk sendmail[18355]: Unable to rename '/usr/local/psa/handlers/spool/messagezLlAN1'...

Php Mail not working