我正在尝试在非互联网机器上安装几个python包。获取错误为

Could not find a version that satisfies the requirement cryptography==3.4.7 (from -r requirements.txt (line 14)) (from versions: )
No matching distribution found for cryptography==3.4.7 (from -r requirements.txt (line 14))

我下载了在线系统中的所有软件包并移动了 requirements.txt 并将软件包文件夹下载到脱机系统中，并尝试使用以下命令在其中安装软件包，

pip3.6 install --no-index --find-links="./tranferred_packages" -r requirements.txt

我遵循的步骤-
安装 virtualenv 与pip联机：

pip install virtualenv --user

创建 virtualenv 找到它的来源

python -m virtualenv myenv
cd myenv 
source bin/activate

安装的软件包使用

pip3 install pkgname

然后呢

pip freeze > requirements.txt

下载包到一个文件夹使用

pip download -r requirements.txt

移动 requirements.txt 并将pkgs文件夹下载到脱机系统中，并尝试使用

pip install --no-index --find-links="./tranferred_packages" -r requirements.txt

详细信息错误为

Collecting cryptography==3.4.7 (from -r requirements.txt (line 14))
  0 location(s) to search for versions of cryptography:
  Could not find a version that satisfies the requirement cryptography==3.4.7 (from -r requirements.txt (line 14)) (from versions: )
Cleaning up...
  Removing source in /tmp/pip-build-beg7uvpz/aws-requests-auth
  Removing source in /tmp/pip-build-beg7uvpz/blist
  Removing source in /tmp/pip-build-beg7uvpz/chardet2
No matching distribution found for cryptography==3.4.7 (from -r requirements.txt (line 14))
Exception information:
Traceback (most recent call last):
  File "/root/venv/lib64/python3.6/site-packages/pip/basecommand.py", line 215, in main
    status = self.run(options, args)
  File "/root/venv/lib64/python3.6/site-packages/pip/commands/install.py", line 346, in run
    requirement_set.prepare_files(finder)
  File "/root/venv/lib64/python3.6/site-packages/pip/req/req_set.py", line 381, in prepare_files
    ignore_dependencies=self.ignore_dependencies))
  File "/root/venv/lib64/python3.6/site-packages/pip/req/req_set.py", line 557, in _prepare_file
    require_hashes
  File "/root/venv/lib64/python3.6/site-packages/pip/req/req_install.py", line 278, in populate_link
    self.link = finder.find_requirement(self, upgrade)
  File "/root/venv/lib64/python3.6/site-packages/pip/index.py", line 514, in find_requirement
    'No matching distribution found for %s' % req
pip.exceptions.DistributionNotFound: No matching distribution found for cryptography==3.4.7 (from -r requirements.txt (line 14))

我有 cryptography 中提到 requirements.txt 以及 cryptography-3.4.7-cp36-abi3-manylinux2014_x86_64.whl 存在于 tranferred_packages 文件夹。

cat requirements.txt | grep cryptography
cryptography==3.4.7

(venv) [root@ip-172-35-10-19 venv]# ls -l tranferred_packages/cryptography-3.4.7-cp36-abi3-manylinux2014_x86_64.whl 
-rwxr-xr-x. 1 root root 3181242 Apr 27 15:05 tranferred_packages/cryptography-3.4.7-cp36-abi3-manylinux2014_x86_64.whl
(venv) [root@ip-172-35-10-19 venv]#

其他包的输出，其中它没有给出错误，

Collecting certifi==2020.4.5.1 (from -r requirements.txt (line 7))
  0 location(s) to search for versions of certifi:
  Found link file:///root/venv/tranferred_packages/certifi-2020.4.5.1-py2.py3-none-any.whl, version: 2020.4.5.1
  Local files found: /root/venv/tranferred_packages/certifi-2020.4.5.1-py2.py3-none-any.whl
  Using version 2020.4.5.1 (newest of versions: 2020.4.5.1)

我可以在创建时安装相同的 virtualenv 但不是在创作的时候 venv .
使用下面的命令创建virtualenv，

pip3 install virtualenv --user

的输出 pip3 list ```

pip3 list |grep cryptography

cryptography 3.4.7

在这个virtualenv中，python和pip版本是，

python python2.7 python3.6 python3.6m python3.6m-x86_64-config
python2 python3 python3.6-config python3.6m-config python3-config

python -V

Python 3.6.8

python3.6 -V

Python 3.6.8

pip pip3 pip-3 pip-3.6 pip3.6

pip-3.6 -V

pip 21.0.1 from /root/oldenv/lib/python3.6/site-packages/pip (python 3.6)

以上所有pip显示版本为 `pip 21.0.1` 除了 `pip-3` 显示版本为， `pip 9.0.3 from /usr/lib/python3.6/site-packages (python 3.6)` 创建virtualenv后安装了以下三个模块

pip 21.0.1
setuptools 56.0.0
wheel 0.34.2

使用以下命令创建venv，

python3.6 -m venv devenv

创建venv后安装以下两个模块，

pip (9.0.3)
setuptools (39.2.0)

系统范围的python和pip版本

python python2.7 python3.6 python3.6m python3.6m-x86_64-config
python2 python3 python3.6-config python3.6m-config python3-config

python --version

Python 2.7.5

python3.6 --version

Python 3.6.8

pip3 pip-3 pip-3.6 pip3.6

pip3.6 -V

pip 9.0.3 from /usr/lib/python3.6/site-packages (python 3.6)

其他详细信息-
rhel 7.8（迈朴）
内核-3.10.0-1127.el7.x86\u 64
有人能说是什么引起了这个问题吗？
谢谢，