# Extensions-Manager: Extensions can not be installed

**URL:** <https://discourse.slicer.org/t/extensions-manager-extensions-can-not-be-installed/46824>\
**Category:** Support\
**Tags:** extensions-manager\
**Created:** [April 24, 2026, 11:49am UTC](https://discourse.slicer.org/t/extensions-manager-extensions-can-not-be-installed/46824 "2026-04-24T11:49:54Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![juliangallaun](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/juliangallaun/32/9545_2.png) [@juliangallaun](https://discourse.slicer.org/u/juliangallaun)\
**Post date:** [April 24, 2026, 11:49am UTC](https://discourse.slicer.org/t/extensions-manager-extensions-can-not-be-installed/46824/1 "2026-04-24T11:49:55Z")

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Hello, I am unable to install new Extensions.

Following message show up.

Extensions can not be installed.  
Failed to load extension page using this URL: [@KitwareMedical/slicer-extensions-webapp](https://extensions.slicer.org/catalog/All/34045/win)  
Check that 3D Slicer is properly installed.

Thanks in advance for your help.

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**Author:** ![pieper](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/pieper/32/8_2.png) [@pieper](https://discourse.slicer.org/u/pieper)\
**Post date:** [April 24, 2026, 12:51pm UTC](https://discourse.slicer.org/t/extensions-manager-extensions-can-not-be-installed/46824/2 "2026-04-24T12:51:37Z")

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That link opens for me, does it for you? Perhaps you are behind some kind of institional firewall.

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**Author:** ![juliangallaun](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/juliangallaun/32/9545_2.png) [@juliangallaun](https://discourse.slicer.org/u/juliangallaun)\
**Post date:** [April 24, 2026, 1:29pm UTC](https://discourse.slicer.org/t/extensions-manager-extensions-can-not-be-installed/46824/3 "2026-04-24T13:29:09Z")

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Could be, I was able to access it a few weeks ago.

Thanks for the fast reply.