Getting warning "systemd: [/usr/lib/systemd/system/ip6tables.service:3] Failed to add dependency on syslog.target,iptables.service, ignoring: Invalid argument".

Issue

• The ip6tables.service unit file is setting as below:

# cat /usr/lib/systemd/system/ip6tables.service                             
[Unit]                                                                                                   
Description=IPv6 firewall with ip6tables                                                                 
After=syslog.target,iptables.service  

• When run systemctl daemon-reload, receive error:

systemd: [/usr/lib/systemd/system/ip6tables.service:3] Failed to add dependency on syslog.target,iptables.service, ignoring: Invalid argument in /var/log/messages.