# Authentication Error when trying to use the Extensions window

**URL:** <https://forums.sketchup.com/t/authentication-error-when-trying-to-use-the-extensions-window/45780>\
**Category:** Warehouses\
**Tags:** extensionwarehouse\
**Created:** [May 31, 2017, 10:01pm UTC](https://forums.sketchup.com/t/authentication-error-when-trying-to-use-the-extensions-window/45780 "2017-05-31T22:01:44Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![billymorris30](https://avatars.discourse-cdn.com/v4/letter/b/958977/32.png) [@billymorris30](https://forums.sketchup.com/u/billymorris30)\
**Post date:** [May 31, 2017, 10:01pm UTC](https://forums.sketchup.com/t/authentication-error-when-trying-to-use-the-extensions-window/45780/1 "2017-05-31T22:01:44Z")

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Hello, I have been a frequent user for Sketchup and have never run into any problems until recently. I tried to go into windows → extensions and sign in/download the STL extension, but each time I try either it get an "Authentication failure, contact the system administrator, reference # 751ace33-b2f9-431d-aac2-44607f9a9079 ". I was wondering if there was a simple fix. I am currently using Sketchup 2016 (64-bit).

Thank you for your time,

William

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**Author:** ![DanRathbun](https://sea2.discourse-cdn.com/sketchup/user_avatar/forums.sketchup.com/danrathbun/32/500_2.png) [@DanRathbun](https://forums.sketchup.com/u/DanRathbun)\
**Post date:** [June 1, 2017, 7:36pm UTC](https://forums.sketchup.com/t/authentication-error-when-trying-to-use-the-extensions-window/45780/2 "2017-06-01T19:36:04Z")

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> [@billymorris30](#):
>
> I tried to go into windows -\> extensions and sign in/download the STL extension, but each time I try either it get an “Authentication failure”, …

Before opening the **Extensions** window,… first sign in by clicking the little person icon on the lower left of the SketchUp application status bar.

Report back.

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**Author:** ![system](https://global.discourse-cdn.com/sketchup/original/3X/f/2/f2a121500b085ed60806607a82720b092d800bb3.png) [@system](https://forums.sketchup.com/u/system)\
**Post date:** [September 1, 2017, 11:36am UTC](https://forums.sketchup.com/t/authentication-error-when-trying-to-use-the-extensions-window/45780/3 "2017-09-01T11:36:18Z")

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Closed on September 1, 2017, 11:36am UTC

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