Lost connection to API on CentOS 7

HI, I'm green on pihole and some question in it. Anyone Can help.. thank a lot.

[root@CentDNS ~]# systemctl status dnsmasq
● dnsmasq.service - DNS caching server.
Loaded: loaded (/usr/lib/systemd/system/dnsmasq.service; enabled; vendor preset: disabled)
Active: active (running) since 一 2018-04-09 14:01:17 CST; 30min ago
Main PID: 1094 (dnsmasq)
CGroup: /system.slice/dnsmasq.service
└─1094 /usr/sbin/dnsmasq -k

4月 09 14:01:17 CentDNS systemd[1]: Started DNS caching server..
4月 09 14:01:17 CentDNS systemd[1]: Starting DNS caching server....

[root@CentDNS ~]#

[root@CentDNS ~]# systemctl status pihole-FTL -l
● pihole-FTL.service - LSB: pihole-FTL daemon
Loaded: loaded (/etc/rc.d/init.d/pihole-FTL; bad; vendor preset: disabled)
Active: active (exited) since 一 2018-04-09 14:01:20 CST; 32min ago
Docs: man:systemd-sysv-generator(8)
Process: 1107 ExecStart=/etc/rc.d/init.d/pihole-FTL start (code=exited, status=0/SUCCESS)

4月 09 14:01:17 CentDNS systemd[1]: Starting LSB: pihole-FTL daemon...
4月 09 14:01:18 CentDNS pihole-FTL[1107]: Not running
4月 09 14:01:19 CentDNS pihole-FTL[1107]: rm: 无法删除"/var/run/pihole/FTL.sock": 没有那个文件或目录
4月 09 14:01:20 CentDNS su[1243]: (to pihole) root on none
4月 09 14:01:20 CentDNS pihole-FTL[1107]: FTL started!
4月 09 14:01:20 CentDNS systemd[1]: Started LSB: pihole-FTL daemon.

[root@CentDNS ~]# service pihole-FTL restart
.Stopped
rm: cannot remove '/var/run/pihole/FTL.sock': No such file or directory
FTL started!

the web interface still in lost connection to api.

MY debug token is: 4h57wercuw

Oh,other information:
Pi-hole Version v3.3.1 Web Interface Version v3.3 FTL Version v3.0

Can you tell me if you /etc/init.d/pihole-FTL.service file is equal to this: https://github.com/pi-hole/pi-hole/blob/master/advanced/pihole-FTL.service

Thanks for your reply.

I compared the local file to the file on the server, which is consistent.

Pihole is a new installation. With the following command:
yum -y install epel-release
yum -y install net-tools
yum -y update
reboot
...
cd /opt
curl -L https://install.pi-hole.net | bash

[root@CentDNS ~]# uname -a
Linux CentDNS 3.10.0-693.21.1.el7.x86_64 #1
[root@CentDNS ~]# cat /etc/redhat-release
Linux release 7.4.1708 (Core)

CentOS installed in the synology virtual machine . The iso file download from https://www.centos.org

/var/run/pihole/FTL.sock is exists..

[root@CentDNS ~]# ls /var/run/pihole/FTL.sock -l

srwxrwxrwx. 1 pihole pihole 0 4月 9 15:05 /var/run/pihole/FTL.sock

BTW. pihole-FTL.service IS pihole-FTL ?

Can you try a pihole -r > Repair?

Try to pihole -r. , but not work.

What behavior do you see now?

Refresh the web times. Same as the previous interface:

the services Status

Can you run through the debugging steps here:

Is that so? What do I need to do next?

What is the output of this command?

echo ">stats" | nc localhost 4711

thank you for your reply..

result is follow:

Make a new debug token if you're still having this issue.