What is the meanings of the message "already exists previous definition" from named?

Issue

• What is the meanings of the message already exists previous definition from named?

• named failed to start with below error.

  # systemctl status named-chroot -l
  ● named-chroot.service - Berkeley Internet Name Domain (DNS)
     Loaded: loaded (/usr/lib/systemd/system/named-chroot.service; disabled; vendor preset: disabled)
     Active: failed (Result: exit-code) since Tue 2023-04-18 09:58:08 JST; 2s ago
    Process: 109267 ExecStop=/bin/sh -c /usr/sbin/rndc stop > /dev/null 2>&1 || /bin/kill -TERM $MAINPID (code=exited, status=0/SUCCESS)
    Process: 75326 ExecReload=/bin/sh -c if /usr/sbin/rndc null > /dev/null 2>&1; then /usr/sbin/rndc reload; else /bin/kill -HUP $MAINPID; fi (code=exited, status=0/SUCCESS)
    Process: 109161 ExecStart=/usr/sbin/named -u named -c ${NAMEDCONF} -t /var/named/chroot $OPTIONS (code=exited, status=0/SUCCESS)
    Process: 109857 ExecStartPre=/bin/bash -c if [ ! "$DISABLE_ZONE_CHECKING" == "yes" ]; then /usr/sbin/named-checkconf -t /var/named/chroot -z "$NAMEDCONF"; else echo "Checking of zone files is disabled"; fi (code=exited, status=1/FAILURE)
   Main PID: 109168 (code=exited, status=0/SUCCESS)
  
  Apr 18 09:58:08 rhel8u6 systemd[1]: Starting Berkeley Internet Name Domain (DNS)...
  Apr 18 09:58:08 rhel8u6 bash[109859]: /etc/named.conf:80: zone 'test.com': already exists previous definition: /etc/named.conf:74
  Apr 18 09:58:08 rhel8u6 systemd[1]: named-chroot.service: Control process exited, code=exited status=1
  Apr 18 09:58:08 rhel8u6 systemd[1]: named-chroot.service: Failed with result 'exit-code'.
  Apr 18 09:58:08 rhel8u6 systemd[1]: Failed to start Berkeley Internet Name Domain (DNS).