Azure Nvidia中的linux-apt更新出现公钥错误

我在AZURE上启动了一个NVIDIA虚拟机，并尝试使用sudo apt update但给出了错误：

Hit:2 http://azure.archive.ubuntu.com/ubuntu focal InRelease                                                 
Hit:3 http://azure.archive.ubuntu.com/ubuntu focal-updates InRelease                                         
Hit:4 http://azure.archive.ubuntu.com/ubuntu focal-backports InRelease                                   
Hit:5 https://packages.microsoft.com/repos/azure-cli focal InRelease        
Hit:6 http://security.ubuntu.com/ubuntu focal-security InRelease            
Err:1 http://developer.download.nvidia.com/compute/cuda/repos/ubuntu2004/x86_64  InRelease
  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY A4B469963BF863CC
Reading package lists... Done
W: GPG error: http://developer.download.nvidia.com/compute/cuda/repos/ubuntu2004/x86_64  InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY A4B469963BF863CC
E: The repository 'http://developer.download.nvidia.com/compute/cuda/repos/ubuntu2004/x86_64  InRelease' is no longer signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.

安装我用过的钥匙sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv A4B469963BF863CC

但这给出了 No data 错误。gpg: keyserver receive failed: No data 

我可以运行sudo apt-get upgrade但不能更新。任何帮助，将不胜感激

即使安装了 cuda，但它仍然找不到 cuda 库，这可能是由于更新。