After Successful Installation DNS server not working..

Hello Everyone,
I installed single server ISPCONFIG 3.2.2 via official auto installer with Nginx server in Ubuntu 20.04
But after install when I added dns zone via wizard and added site too. but it's still not working after 12 hours. (i setup custom nameserver with my ispconfig machine Public ip address in my domain registrar before that.)
Now I don't know what's the problem...
here is my test script results....

Code:

##### SERVER #####
IP-address (as per hostname): ***.***.***.***
[WARN] could not determine server's ip address by ifconfig
[INFO] OS version is Ubuntu 20.04.2 LTS

[INFO] uptime:  06:12:36 up 17 min,  1 user,  load average: 0.14, 0.14, 0.19

[INFO] memory:
              total        used        free      shared  buff/cache   available
Mem:          1.9Gi       1.5Gi        88Mi        41Mi       348Mi       239Mi
Swap:         511Mi        29Mi       482Mi

[INFO] systemd failed services status:
  UNIT                      LOAD   ACTIVE SUB    DESCRIPTION
● console-setup.service     loaded failed failed Set console font and keymap
● snap.lxd.activate.service loaded failed failed Service for snap application lxd.activate

LOAD   = Reflects whether the unit definition was properly loaded.
ACTIVE = The high-level unit activation state, i.e. generalization of SUB.
SUB    = The low-level unit activation state, values depend on unit type.

2 loaded units listed.

[INFO] ISPConfig is installed.

##### ISPCONFIG #####
ISPConfig version is 3.2.2


##### VERSION CHECK #####

[INFO] php (cli) version is 7.4.15

##### PORT CHECK #####

[WARN] Port 443 (Webserver SSL) seems NOT to be listening

##### MAIL SERVER CHECK #####


##### RUNNING SERVER PROCESSES #####

[INFO] I found the following web server(s):
        Unknown process (nginx:) (PID 662)
[INFO] I found the following mail server(s):
        Postfix (PID 1653)
[INFO] I found the following pop3 server(s):
        Dovecot (PID 544)
[INFO] I found the following imap server(s):
        Dovecot (PID 544)
[INFO] I found the following ftp server(s):
        PureFTP (PID 1002)

##### LISTENING PORTS #####
(only           ()
Local           (Address)
[anywhere]:25           (1653/master)
[localhost]:953         (560/named)
[anywhere]:4190         (544/dovecot)
[anywhere]:993          (544/dovecot)
[anywhere]:995          (544/dovecot)
[localhost]:11332               (620/rspamd:)
[localhost]:11333               (620/rspamd:)
[localhost]:11334               (620/rspamd:)
[localhost]:10023               (905/postgrey)
[anywhere]:587          (1653/master)
[localhost]:6379                (763/redis-server)
[localhost]:11211               (559/memcached)
[anywhere]:110          (544/dovecot)
[anywhere]:143          (544/dovecot)
[anywhere]:80           (662/nginx:)
[anywhere]:8080         (662/nginx:)
[anywhere]:465          (1653/master)
[anywhere]:8081         (662/nginx:)
[anywhere]:21           (1002/pure-ftpd)
***.***.***.***:53              (560/named)
[localhost]:53          (560/named)
***.***.***.***:53              (528/systemd-resolve)
[anywhere]:22           (648/sshd:)
*:*:*:*::*:25           (1653/master)
*:*:*:*::*:953          (560/named)
*:*:*:*::*:4190         (544/dovecot)
*:*:*:*::*:993          (544/dovecot)
*:*:*:*::*:995          (544/dovecot)
*:*:*:*::*:3306         (850/mysqld)
*:*:*:*::*:587          (1653/master)
*:*:*:*::*:6379         (763/redis-server)
[localhost]10           (544/dovecot)
[localhost]43           (544/dovecot)
*:*:*:*::*:80           (662/nginx:)
*:*:*:*::*:8080         (662/nginx:)
*:*:*:*::*:465          (1653/master)
*:*:*:*::*:8081         (662/nginx:)
*:*:*:*::*:21           (1002/pure-ftpd)
*:*:*:*::*f03c:92ff:fe95:53             (560/named)
*:*:*:*::*f03c:92ff:53          (560/named)
*:*:*:*::*:53           (560/named)
*:*:*:*::*:22           (648/sshd:)




##### IPTABLES #####
Chain INPUT (policy ACCEPT)
target     prot opt source               destination
f2b-sshd   tcp  --  [anywhere]/0            [anywhere]/0            multiport dports 22

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination

Chain f2b-sshd (1 references)
target     prot opt source               destination
REJECT     all  --  ***.***.***.***      [anywhere]/0            reject-with icmp-port-unreachable
REJECT     all  --  ***.***.***.***         [anywhere]/0            reject-with icmp-port-unreachable
RETURN     all  --  [anywhere]/0            [anywhere]/0

 

My php version is 7.4.15
and here is my dig @localhost mydomain.com result (I just anonymous my domain)

Code:

; <<>> DiG 9.16.1-Ubuntu <<>> @localhost mydomain.com
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 11505
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
; COOKIE: 6cd71408f6acc71901000000603c89f2c3a6b50e1a96d13a (good)
;; QUESTION SECTION:
;mydomain.com.                  IN      A

;; Query time: 4999 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Mon Mar 01 06:30:10 UTC 2021
;; MSG SIZE  rcvd: 69

 

Till sir, thanks for for your reply,
When I checked my dns settings in my ispconfig, I found out that ns1 and ns2 is automatically created,
Here is my screenshot for better understand...

 

Thank you sir, it's working now..
I just added 2 new A record (ns1, ns2) as you told...
thanks again..

 

There is link to DNS tutorial in my signature.