ParthPadmawar Hi mate, is your internet connection strong? Also have you tried checking for an update via settings>system>system update
I’d advise re-trying to download the update while connected to a different Wi-Fi network if possible. If you continue to receive an error you could (if you have access to one) try a VPN that connects you to a server outside your country and re-attempt the download
If you continue to receive the error, please contact Nothing Support… settings>system>support