解决 An HTTP error occurred when trying to retrieve this URL.问题

问题：

An HTTP error occurred when trying to retrieve this URL.
HTTP errors are often intermittent, and a simple retry will get you on your way.

If your current network has https://www.anaconda.com blocked, please file
a support request with your network engineering team.

'https://repo.anaconda.com/pkgs/main/linux-64'

原因是conda源加入了不知名的URL，现在不能使用了（或者废弃）

解决方案：

#重置源配置
conda config --remove-key channels
#重新添加清华源
>conda config --add channels https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free/
 conda config --add channels https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/main/
 conda config --add channels https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud/pytorch/
 conda config --set show_channel_urls yes