UnavailableInvalidChannel: The channel is not accessible or is invalid.

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,
…

清华源不可用
恢复默认配置即可，若不行，可配置代理 科学上网。

conda config --remove-key channels

接下来一切按照正常的安装即可。