Anaconda安装包报错——UnavailableInvalidChannel: The channel is not accessible or is invalid

报错

UnavailableInvalidChannel: The channel is not accessible or is invalid.
      channel name: anaconda/pkgs/free
      channel url: https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free
      error code: 404
    
    You will need to adjust your conda configuration to proceed.
    Use `conda config --show channels` to view your configuration's current state,
    and use `conda config --show-sources` to view config file locations.

解决办法：使用以下命令恢复默认源

conda config --remove-key channels