"DLL load failed" when import cv2 (opencv)

In [windows server 2012 R2 x64, python 3.7 64x]

pip install opencv-contrib-python

installed without any error .
and when I try to import it

import cv2

show me this error :

Traceback (most recent call last):
  File "test.py", line 1, in <module>
    import cv2
  File "C:\Program Files\Python37\lib\site-packages\cv2\__init__.py", line 3, in
 <module>
    from .cv2 import *
ImportError: DLL load failed: The specified module could not be found.

and I see another topic about this error but their solution does not work for me :
- DLL load failed error when importing cv2
- Failure to import cv2 in python : DLL load failed
- and a lot of pages in here

some of them say about that problem because anaconda, and I don't have anaconda even. and many say that problem 32 or 64 version, I try both and disappointment. many about system variables...
what dll failed to load? cv2? why?

what i try till now:

• change python version : 3.5, 3.7, 2.7 in 86x and 64x (uninstall complete last version and delete all remain files in program files ... then install new one)

• try with another packages like : opencv-python, opencv-contrib, try install specific versions with .whl (in some topic i read about this so install numpy-1.14.5+mkl-cp37-cp37m-win_amd64.whl and opencv_python-3.4.3+contrib-cp37-cp37m-win_amd64.whl but anything not change)

• import numpy before cv2 for every test

• installed Microsoft Visual C++ 2015 Redistributable Update 3 , 2008 , 2010 , 2017 for 64x

UPDATE
NEXT 2 DAY

I try to manage missing dll base on dependency walker that mention in bellow post, download all dll and put them in system 32, its a good clue but not solve the problem.

DAY 4,5

my next step , trying compile OpenCV in my machine , install visual studio 2012 + cmake and base on document compile 2 version , 64x and 32 , compiling have a lot of problem itself (like missing some lib from c lang and need to install Visual C++ Redistributable for Visual Studio 2012 ...) and I resolve all of them ,then I have 2 success compiled version but both have the same problem with missing dll, the compile process is so slow and give 2 day from me. so if fail on this mission :/ I search for a new way...

DAY 6

my next step is to try to run OpenCV in my machine with docker ( I try but docker windows just install on windows 10 and windows server 2016) so I search for an alternative. I found Vagrant that work like docker but with VM (visual box) today my time spend for this articles, it's amazing, the concept of docker and vagrant is so Attractive, and I play with this like that I have new puzzle :) first error show on ... and limitless errors go on :

Day 7

Vagrant tests failed too because my windows server 2012 is a vb machine (visual server) and run a visual box in another visual box impossible! so I need new clues :

Day 8-9

try install vagrant with VMware , I download VMware, unfortunately this plugin is not free (79$) so I try to work with pythonanywhere.com that 'gives you access to machines with a full Python environment already installed.' in this free account, you can't openurl with urllib , and more limit... so I wanna try to install ubuntu in VMware my self... I read here results after work. it's Impossible with same reason vb (visual box)