Unable to start the vsftpd service

Issue

• While trying to enable IPv6 in vsftpd.conf, the service is not able to start.

  # systemctl status vsftpd
  vsftpd.service - Vsftpd ftp daemon
  Loaded: loaded (/usr/lib/systemd/system/vsftpd.service; enabled; vendor preset: disabled)
  Active: failed (Result: exit-code) since Fri 2022-08-26 14:05:30 IST; 37min ago
  Process: 44358 ExecStart=/usr/sbin/vsftpd /etc/vsftpd/vsftpd.conf (code=exited, status=1/FAILURE)
  Main PID: 39552 (code=killed, signal=TERM)
  Aug 26 14:05:27 node1.example.com systemd[1]: Starting Vsftpd ftp daemon...
  Aug 26 14:05:30 node1.example.com systemd[1]: vsftpd.service: Control process exited, code=exited status=1
  Aug 26 14:05:30 node1.example.com systemd[1]: vsftpd.service: Failed with result 'exit-code'.
  Aug 26 14:05:30 node1.example.com systemd[1]: Failed to start Vsftpd ftp daemon.
  

• How to enable ipv6 only and disable ipv4 support for vsftpd service ?