# Unable to download extensions from the extensions manager

**URL:** <https://discourse.slicer.org/t/unable-to-download-extensions-from-the-extensions-manager/20618>\
**Category:** Support\
**Tags:** extensions-manager\
**Created:** [November 15, 2021, 2:33am UTC](https://discourse.slicer.org/t/unable-to-download-extensions-from-the-extensions-manager/20618 "2021-11-15T02:33:53Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![nforwood](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/nforwood/32/13116_2.png) [@nforwood](https://discourse.slicer.org/u/nforwood)\
**Post date:** [November 15, 2021, 2:33am UTC](https://discourse.slicer.org/t/unable-to-download-extensions-from-the-extensions-manager/20618/1 "2021-11-15T02:33:53Z")

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Operating system: Windows 10  
Slicer version:4.11.20210226  
Expected behavior: Download works  
Actual behavior: Get an error “Error retrieving extension metadata: 60ae226cae4540bf6a89da9d ({303b7c63-e615-43d7-9232-688ef5bec7c9}: 5: Operation canceled)”…

I can’t seem to download any extension from the extension manager. I just get the error above. I also can’t manually download the extensions from the website. I am in a corporate network but usually this hasn’t bean a problem for other applictions.

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**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [November 15, 2021, 9:57pm UTC](https://discourse.slicer.org/t/unable-to-download-extensions-from-the-extensions-manager/20618/2 "2021-11-15T21:57:58Z")

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The extension server was replaced and too aggressive corporate network/proxy are expected to cause more issues than before. You may find this discussion helpful:

> [@New extension manager and issues with corporate certificates](https://discourse.slicer.org/t/new-extension-manager-and-issues-with-corporate-certificates/19361/36):
>
> You can open the local machine certificate manager by hitting the windows key and typing certlm.msc. You can then find the self-signed certificate and disable all uses, restart the computer, and see if wget in python still works. You can also [run wget step by step in a Python debugger](https://github.com/SlicerRt/SlicerDebuggingTools/blob/master/README.md#debuggingtools-extension-for-3d-slicer) to see what certificates it is using and from where it gets them.

We have an other ongoing investigation of problems downloading behind netskope proxy. Is that what your corporate network uses, too?

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**Author:** ![muratmaga](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/muratmaga/32/3622_2.png) [@muratmaga](https://discourse.slicer.org/u/muratmaga)\
**Post date:** [November 15, 2021, 11:22pm UTC](https://discourse.slicer.org/t/unable-to-download-extensions-from-the-extensions-manager/20618/3 "2021-11-15T23:22:40Z")

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@nforwood we are behind a corporate firewall and use self-signed certificates. As indicated in the discussion linked, importing certificates into slicer.crt solves part of the equation. but even then we had a lot of issues (e.g., pip\_install’s didn’t work because firewall ended up blocking). So you might have to work with your IT department to find a solution (exceptions, firewall rule changes for specific ITs etc) that will work with your particular situation.