email server – postfix/qmgr: warning: qmgr_active_done_3_generic: remove BCD2761F9C from active: No such file …rectory

I have a CentOS 7 with postfix and dovecot and dovecot-mysql installed. Receiving the errors shown:

Sep 05 02:17:32 example.com postfix/qmgr[22004]: warning: qmgr_active_done_3_generic: remove BCD2761F9C from active: No such file …rectory

I do not understand the message warning: No such file or directory..
Is this related with PHPMailer; since I am using PHPMailer to send emails?