In ubuntu server apt-get update showing proxy server error

Question

I am trying to update packages on Ubuntu server 22.10 which is running on a Raspberry Pi 4B, that is being used as a remote server. There is no error in the DNS I tried ping google.com and it is working properly.

--- google.com ping statistics --- 9 packets transmitted, 9 received, 0% packet loss, time 8013ms rtt min/avg/max/mdev = 6.560/6.795/6.941/0.126

I'm not sure about my UFW firewall port. And do let me know if there's been any mistake in opening or closing any ports.

ufw firewall status

root@ubuntu:~# sudo ufw status
Status: active
To                         Action      From

10000                      ALLOW       Anywhere

22/tcp                     ALLOW       Anywhere

80/tcp                     ALLOW       Anywhere

443                        ALLOW       Anywhere

80                         ALLOW       Anywhere

53                         ALLOW       Anywhere

443/tcp                    ALLOW       Anywhere

9200                       ALLOW       Anywhere

10000 (v6)                 ALLOW       Anywhere (v6)

22/tcp (v6)                ALLOW       Anywhere (v6)

80/tcp (v6)                ALLOW       Anywhere (v6)

80 (v6)                    ALLOW       Anywhere (v6)

53 (v6)                    ALLOW       Anywhere (v6)

443/tcp (v6)               ALLOW       Anywhere (v6)

443 (v6)                   ALLOW       Anywhere (v6)

9200 (v6)                  ALLOW       Anywhere (v6)

Error that it's showing

root@ubuntu:~# sudo apt-get update
Ign:1 http://download.opensuse.org/repositories/isv:/ownCloud:/server:/10/Ubuntu_21.10  InRelease
Ign:2 http://ports.ubuntu.com/ubuntu-ports kinetic InRelease
Ign:3 https://ppa.launchpadcontent.net/ondrej/php/ubuntu kinetic InRelease
Ign:4 http://ports.ubuntu.com/ubuntu-ports kinetic-updates InRelease
Ign:5 http://ports.ubuntu.com/ubuntu-ports kinetic-backports InRelease
Ign:6 http://ports.ubuntu.com/ubuntu-ports kinetic-security InRelease
Ign:1 http://download.opensuse.org/repositories/isv:/ownCloud:/server:/10/Ubuntu_21.10  InRelease
Ign:2 http://ports.ubuntu.com/ubuntu-ports kinetic InRelease
Ign:3 https://ppa.launchpadcontent.net/ondrej/php/ubuntu kinetic InRelease
Ign:4 http://ports.ubuntu.com/ubuntu-ports kinetic-updates InRelease
Ign:5 http://ports.ubuntu.com/ubuntu-ports kinetic-backports InRelease
Ign:6 http://ports.ubuntu.com/ubuntu-ports kinetic-security InRelease
Ign:1 http://download.opensuse.org/repositories/isv:/ownCloud:/server:/10/Ubuntu_21.10  InRelease
Ign:2 http://ports.ubuntu.com/ubuntu-ports kinetic InRelease
Ign:3 https://ppa.launchpadcontent.net/ondrej/php/ubuntu kinetic InRelease
Ign:4 http://ports.ubuntu.com/ubuntu-ports kinetic-updates InRelease
Ign:5 http://ports.ubuntu.com/ubuntu-ports kinetic-backports InRelease
Ign:6 http://ports.ubuntu.com/ubuntu-ports kinetic-security InRelease
Err:1 http://download.opensuse.org/repositories/isv:/ownCloud:/server:/10/Ubuntu_21.10  InRelease
  Temporary failure resolving 'proxyserver'
Err:2 http://ports.ubuntu.com/ubuntu-ports kinetic InRelease
  Temporary failure resolving 'proxyserver'
Err:3 https://ppa.launchpadcontent.net/ondrej/php/ubuntu kinetic InRelease
  Temporary failure resolving 'proxyserver'
Err:4 http://ports.ubuntu.com/ubuntu-ports kinetic-updates InRelease
  Temporary failure resolving 'proxyserver'
Err:5 http://ports.ubuntu.com/ubuntu-ports kinetic-backports InRelease
  Temporary failure resolving 'proxyserver'
Err:6 http://ports.ubuntu.com/ubuntu-ports kinetic-security InRelease
  Temporary failure resolving 'proxyserver'
Reading package lists... Done
W: Failed to fetch http://ports.ubuntu.com/ubuntu-ports/dists/kinetic/InRelease  Temporary failure resolving 'proxyserver'
W: Failed to fetch http://ports.ubuntu.com/ubuntu-ports/dists/kinetic-updates/InRelease  Temporary failure resolving 'proxyserver'
W: Failed to fetch http://ports.ubuntu.com/ubuntu-ports/dists/kinetic-backports/InRelease  Temporary failure resolving 'proxyserver'
W: Failed to fetch http://ports.ubuntu.com/ubuntu-ports/dists/kinetic-security/InRelease  Temporary failure resolving 'proxyserver'
W: Failed to fetch http://download.opensuse.org/repositories/isv:/ownCloud:/server:/10/Ubuntu_21.10/InRelease  Temporary failure resolving 'proxyserver'
W: Failed to fetch https://ppa.launchpadcontent.net/ondrej/php/ubuntu/dists/kinetic/InRelease  Temporary failure resolving 'proxyserver'
W: Some index files failed to download. They have been ignored, or old ones used instead.

No proxy server is created which has been checked by using this code of lines

echo "$http_proxy"
echo "$https_proxy"
env | grep proxy

All the above shows no output, and nothing is there even in sudo nano /etc/apt/apt.conf.

I want to get it back to the normal way it used to get updated and upgraded, and I want to delete unwanted UFW ports, which can be harmful for the server's security.

Edit:::::: For further discussion and solution please check https://ubuntuforums.org/showthread.php?t=2484973&p=14136226#post14136226