no cron jobs in this account.
I check on email log
Mar 17 00:30:59 ashokathi logger: sendmail: CALLER="php-fpm: pool atkfashion" PWD="/home/atkfashion/public_html/wp-content/plugins/yith-woocommerce-ajax-navigation/plugin-fw" BAN="no"
Mar 17 00:30:59 ashokathi send: delivery 4359: success: did_0+0+1/
Mar 17 00:30:59 ashokathi send: status: local 0/10 remote 7/60
Mar 17 00:30:59 ashokathi send: end msg 41038460
Mar 17 00:30:59 ashokathi send: delivery 4353: success: User_and_password_not_set,_continuing_without_authentication./<dweed170@gmail.com>_74.125.193.26_accepted_message./Remote_host_said:_250_2.0.0_OK_1458153026_b6si6571939ioj.13_-_gsmtp/
Mar 17 00:30:59 ashokathi send: status: local 0/10 remote 6/60
Mar 17 00:30:59 ashokathi send: end msg 41038321
Mar 17 00:30:59 ashokathi send: new msg 41038321
Mar 17 00:30:59 ashokathi send: info msg 41038321: bytes 1290 from <toni_berry@atkfashionltd.com> qp 9907 uid 7822
Mar 17 00:30:59 ashokathi send: starting delivery 4360: msg 41038321 to remote gregorymclifton88@gmail.com
Mar 17 00:30:59 ashokathi send: status: local 0/10 remote 7/60
Mar 17 00:30:59 ashokathi logger: sendmail: CALLER="php-fpm: pool atkfashion" PWD="/home/atkfashion/public_html/wp-content/plugins/yith-woocommerce-ajax-navigation/plugin-fw" BAN="no"
You can see WP WooCommerce plugin sent too much email from my vps.
and ashokathi is my FQDN.