# Problem Paraview/VTK

**URL:** https://discourse.vtk.org/t/problem-paraview-vtk/6104
**Category:** Support
**Created:** [June 30, 2021, 9:37am UTC](https://discourse.vtk.org/t/problem-paraview-vtk/6104 "2021-06-30T09:37:17Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![Luis\_Carlos\_Carneiro](https://discourse.vtk.org/user_avatar/discourse.vtk.org/luis_carlos_carneiro/32/1360_2.png) [@Luis\_Carlos\_Carneiro](https://discourse.vtk.org/u/Luis_Carlos_Carneiro)
#### Post date: [June 30, 2021, 9:37am UTC](https://discourse.vtk.org/t/problem-paraview-vtk/6104/1 "2021-06-30T09:37:17Z")

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Dear All,

When I run the example “web-project-templates-master” in Windows gives the following error:

```auto
C:\Users\Luis.Goncalves_ext\novo_botao>"C:\Program Files\ParaView 5.9.1-Windows-Python3.8-msvc2017-64bit\bin\pvpython" .\server\vtkpython\vtkw-server.py --content .\dist --port 1234
Traceback (most recent call last):
  File ".\server\vtkpython\vtkw-server.py", line 40, in <module>
    from wslink import server
  File "C:\Program Files\ParaView 5.9.1-Windows-Python3.8-msvc2017-64bit\bin\Lib\site-packages\wslink\server.py", line 16, in <module>
    from wslink import websocket as wsl
  File "C:\Program Files\ParaView 5.9.1-Windows-Python3.8-msvc2017-64bit\bin\Lib\site-packages\wslink\websocket.py", line 18, in <module>
    from autobahn.twisted.websocket import WebSocketServerFactory
  File "C:\Program Files\ParaView 5.9.1-Windows-Python3.8-msvc2017-64bit\bin\Lib\site-packages\autobahn\twisted\ __init__.py", line 54, in <module>
    from autobahn.twisted.wamp import ApplicationSession
  File "C:\Program Files\ParaView 5.9.1-Windows-Python3.8-msvc2017-64bit\bin\Lib\site-packages\autobahn\twisted\wamp.py", line 48, in <module>
    from autobahn.wamp import protocol, auth
  File "C:\Program Files\ParaView 5.9.1-Windows-Python3.8-msvc2017-64bit\bin\Lib\site-packages\autobahn\wamp\auth.py", line 40, in <module>
    from cryptography.hazmat.primitives.kdf.pbkdf2 import PBKDF2HMAC
ModuleNotFoundError: No module named 'cryptography'

```

Can you please give a solution?

Thanks,

Luís Gonçalves

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<div class="post-metadata">

### Author: ![mwestphal](https://discourse.vtk.org/user_avatar/discourse.vtk.org/mwestphal/32/19_2.png) [@mwestphal](https://discourse.vtk.org/u/mwestphal)
#### Post date: [June 30, 2021, 9:40am UTC](https://discourse.vtk.org/t/problem-paraview-vtk/6104/2 "2021-06-30T09:40:40Z")

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This is a bug in ParaView 5.9.1, fixed in master.

If you have any follow up question, please ask on ParaView discourse.  
[https://discourse.paraview.org/](https://discourse.paraview.org/)

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<div class="post-metadata">

### Author: ![mwestphal](https://discourse.vtk.org/user_avatar/discourse.vtk.org/mwestphal/32/19_2.png) [@mwestphal](https://discourse.vtk.org/u/mwestphal)
#### Post date: [June 30, 2021, 9:40am UTC](https://discourse.vtk.org/t/problem-paraview-vtk/6104/3 "2021-06-30T09:40:43Z")

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