The reason could be a connection block between the device and update server by your ISP(Internet Service Provider).
???? Please try a couple of things below to see if it helps.
- Verify that you have stable internet connection to your device by opening YouTube and playing a video.
- Clear 'Software Update' app ( Home > Settings > Apps > Find Software Update app and clear data/cache)
- Open the Market app and install the latest "Software Update" app and try the update again.
- Try to connect the internet using your mobile hotspot instead of home network.
- Try to use VPN - Apps are available at Home > Market for download. (e.g., Express VPN, Nord VPN and etc)
Sign up with your VPN provider, Turn on the VPN and try software update. - Perform a Factory Reset ???? How to factory reset your device