Bluethooth, Software problem

Hello,
I'm facing a couple of issues here. Firstly, there's a problem with Bluetooth. Sometimes it works smoothly, Like this:

while other times it behaves erratically as shown in the picture below:

Secondly, there's a software issue. When I boot into Zorin OS, I encounter this error from the software updater:


Additionally, when I attempt to change my mirror and click OK, I receive these messages:


I appreciate any help. The Bluetooth thing is the most important one

I'm from Iran, I'm running Zorin OS 16 alongside Windows 10 on an HP ProBook 4530s.

Could You open the Terminal and type sudo apt update && sudo apt upgrade and show here the Output? In general I would say that it is good to set the Sources to Main Server and not to a regional Server. But it depends on the individual Situation.

Certainly! here is the out put:

barbod@Barbood-NoteBook:~$ sudo apt update && sudo apt upgrade
[sudo] password for barbod:              
Get:1 http://security.ubuntu.com/ubuntu focal-security InRelease [114 kB]
Hit:2 http://archive.ubuntu.com/ubuntu focal InRelease               
Hit:3 http://ir.archive.ubuntu.com/ubuntu focal-updates InRelease    
Hit:4 http://ir.archive.ubuntu.com/ubuntu focal-backports InRelease  
Hit:5 http://ppa.launchpad.net/zorinos/apps/ubuntu focal InRelease   
Hit:6 https://pkg.cloudflareclient.com focal InRelease               
Hit:7 http://ppa.launchpad.net/zorinos/drivers/ubuntu focal InRelease
Hit:8 http://ppa.launchpad.net/zorinos/patches/ubuntu focal InRelease
Get:9 http://ppa.launchpad.net/zorinos/stable/ubuntu focal InRelease [18.1 kB]
Hit:11 https://repo.steampowered.com/steam stable InRelease          
Hit:12 https://packages.zorinos.com/stable focal InRelease          
Ign:10 https://403.online/repos/code stable InRelease                
Hit:13 https://packages.zorinos.com/patches focal InRelease          
Get:14 https://apt.kitware.com/ubuntu focal InRelease [15.5 kB]      
Hit:15 https://packages.zorinos.com/apps focal InRelease             
Hit:17 https://packages.zorinos.com/drivers focal InRelease
Hit:18 https://packages.zorinos.com/premium focal InRelease    
Err:14 https://apt.kitware.com/ubuntu focal InRelease          
  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 1A127079A92F09ED
Get:16 https://packages.microsoft.com/repos/code stable Release [3,065 B]
Get:19 https://packages.microsoft.com/repos/code stable Release.gpg [481 B]
Fetched 151 kB in 4s (36.2 kB/s)    
Reading package lists... Done
Building dependency tree       
Reading state information... Done
1 package can be upgraded. Run 'apt list --upgradable' to see it.
W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: https://apt.kitware.com/ubuntu focal InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 1A127079A92F09ED
W: Failed to fetch https://apt.kitware.com/ubuntu/dists/focal/InRelease  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 1A127079A92F09ED
W: Some index files failed to download. They have been ignored, or old ones used instead.
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Calculating upgrade... Done
The following packages were automatically installed and are no longer required:
  adwaita-qt coinor-libcbc3 coinor-libcgl1 coinor-libclp1 coinor-libcoinmp1v5 coinor-libcoinutils3v5 coinor-libosi1v5 libfuse3-3 libnss3-tools libxmlsec1
  libxmlsec1-nss
Use 'sudo apt autoremove' to remove them.
The following packages have been kept back:
  xdg-desktop-portal
0 upgraded, 0 newly installed, 0 to remove and 1 not upgraded.

Sources are also set to Main server and tested, same as before. Any solution?

As far as I can see You have a Problem with that apt.kitware.com Repo (Entry 14). I don't know what this is for but when you don't need it anymore You should delete it and try it again. And you have an ignored One: Entry 10: 403.online.

recently, I've come across a fresh error:


I suspect either the ISP or Zorin OS has restricted access for Iranians using IP addresses or similar means. However, I'm unsure how to address the Bluetooth issue. Despite being mostly off, the panel consistently shows me to turn off Bluetooth. Occasionally, it operates smoothly. I attempted to resolve the matter using Blueman, but it didn't work

Zorin OS does not and will not restrict any of your sources or access.
You might check in Software & Updates > Other software and set "Download from:" to Main server

The sources show as set to the Iranian Regional Server, not Main Server.

I've changed that and added the required key using this code below:

sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 1A127079A92F09ED

The software problem is solved, but I'm still having problem with the Bluetooth

You can start a new thread about the Bluetooth issue, listing the terminal output of

sudo lshw -C network

to start.