我得到了同样的错误:

WARNING: pip is configured with locations that require TLS/SSL, however the ssl module in Python is not available.
WARNING: Retrying (Retry(total=4, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError("Can't connect to HTTPS URL because the SSL module is not available.")': /simple/pb-tool/
WARNING: Retrying (Retry(total=3, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError("Can't connect to HTTPS URL because the SSL module is not available.")': /simple/pb-tool/
ERROR: Operation cancelled by user
WARNING: pip is configured with locations that require TLS/SSL, however the ssl module in Python is not available.
Could not fetch URL https://pypi.org/simple/pip/: There was a problem confirming the ssl certificate: HTTPSConnectionPool(host='pypi.org', port=443): Max retries exceeded with url: /simple/pip/ (Caused by SSLError("Can't connect to HTTPS URL because the SSL module is not available.")) - skipping

在《Anaconda》中，我使用了以下命令:

conda install anaconda-navigator

本文中提到:pip配置了需要TLS/SSL的位置，但是Python中的SSL模块不可用

我用的是macOS，我用过brew，但Vaulstein在他的回答中提到的并没有涵盖我的情况。

我运行以下命令，以确保我当前的python没有通过brew安装

brew list | grep python           
python
python@2

brew info python
python@3.8: stable 3.8.3 (bottled)
Interpreted, interactive, object-oriented programming language
https://www.python.org/
Not installed
... 

所以我从https://www.python.org/下载了最新的3.8.5，安装时我看到了以下信息

证书验证和OpenSSL 此包包含自己的私有OpenSSL 1.1.1副本。的 管理的系统和用户密钥链中的信任证书 Python ssl模块不默认使用Keychain Access应用程序和安全命令行实用程序

在安装3.8.5之后，它修复了这个问题。

我简单地用以下命令解决了这个问题:

Brew升级python@3.9

这个版本默认包含SSL !

你可以尝试brew链接，它会告诉你正确的说明:

$ brew link openssl --force
Warning: Refusing to link macOS provided/shadowed software: openssl@1.1
If you need to have openssl@1.1 first in your PATH run:
  echo 'export PATH="/usr/local/opt/openssl@1.1/bin:$PATH"' >> ~/.zshrc

For compilers to find openssl@1.1 you may need to set:
  export LDFLAGS="-L/usr/local/opt/openssl@1.1/lib"
  export CPPFLAGS="-I/usr/local/opt/openssl@1.1/include"

For pkg-config to find openssl@1.1 you may need to set:
  export PKG_CONFIG_PATH="/usr/local/opt/openssl@1.1/lib/pkgconfig"

Windows 10, Windows 7 如果pip install在CMD提示符下不工作，使用Anaconda提示符运行它-它工作。

https://github.com/pypa/virtualenv/issues/1139

与上述解决方案类似，使用pyenv重新安装python版本。

不知何故，我升级了我的openssl，它破坏了pyenv版本的python。

pyenv install 3.6.8
python-build: use openssl@1.1 from homebrew
python-build: use readline from homebrew
...

第一行说它依赖于自制的openssl。