virtualenvのインストール中のエラーの解決方法

下記サイトを参考に、Rでディープラーニングをしたいと考えています。
https://clean-copy-of-onenote.hatenablog.com/entry/r/keras_intro

その過程で、Anaconda Promptでvirtualenvのインストールをしたいです。
しかし、「pip install virtualenv」で実行するとエラーが生じました。解決策を教えて頂けると幸いです。
エラーメッセージは以下の通りです。

(C:\ProgramData\Anaconda3) C:\Users\qnd-admin>pip install virtualenv
Collecting virtualenv
Retrying (Retry(total=4, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError('<urllib3.connection.VerifiedHTTPSConnection object at 0x00000268482F49B0>: Failed to establish a new connection: [Errno 11001] getaddrinfo failed',)': /simple/virtualenv/
Retrying (Retry(total=3, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError('<urllib3.connection.VerifiedHTTPSConnection object at 0x00000268482F4518>: Failed to establish a new connection: [Errno 11001] getaddrinfo failed',)': /simple/virtualenv/
Retrying (Retry(total=2, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError('<urllib3.connection.VerifiedHTTPSConnection object at 0x00000268482F46D8>: Failed to establish a new connection: [Errno 11001] getaddrinfo failed',)': /simple/virtualenv/
Retrying (Retry(total=1, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError('<urllib3.connection.VerifiedHTTPSConnection object at 0x00000268482F4390>: Failed to establish a new connection: [Errno 11001] getaddrinfo failed',)': /simple/virtualenv/
Retrying (Retry(total=0, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError('<urllib3.connection.VerifiedHTTPSConnection object at 0x00000268482F42B0>: Failed to establish a new connection: [Errno 11001] getaddrinfo failed',)': /simple/virtualenv/
Could not find a version that satisfies the requirement virtualenv (from versions: )
No matching distribution found for virtualenv