# PDF viewer is not recognizing my license key

**URL:** <https://pdfjs.community/t/pdf-viewer-is-not-recognizing-my-license-key/1353>\
**Category:** Technical Support\
**Created:** [February 7, 2022, 7:52pm UTC](https://pdfjs.community/t/pdf-viewer-is-not-recognizing-my-license-key/1353 "2022-02-07T19:52:29Z")\
**Posts on this page:** 1\
**Showing post:** 3

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**Author:** ![system](https://canada1.discourse-cdn.com/flex031/uploads/pdfjscommunity/original/1X/ffbcd25c7d423db8d5acd5db201c272f4db306dd.png) [@system](https://pdfjs.community/u/system)\
**Post date:** [February 7, 2022, 7:52pm UTC](https://pdfjs.community/t/pdf-viewer-is-not-recognizing-my-license-key/1353/3 "2022-02-07T19:52:34Z")

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**Hello, I’m Ron, an automated tech support bot 🤖**

While you wait for one of our customer support representatives to get back to you, please check out some of these documentation pages:

Guides:
- [Adding your license key](https://pdfjs.express/documentation/get-started-viewer/add-license-key)
- [Migrating from PDF.js Express to PDFTron - 3. Change initiation](https://pdfjs.express/documentation/learn-more/pdfjs-express-to-pdftron.8#3.-change-initiation)
- [Integrating PDF.js Express Plus into a new Blazor project - Prerequisites](https://pdfjs.express/documentation/get-started/blazor/new-project#prerequisites)

APIs:
- [Core - preloadPDFWorker(pdfBackendType, workerHandlers)](https://pdfjs.express/api/Core.html#.preloadPDFWorker__anchor)
- [Core.Annotations.RotationUtils - RectangularCustomAnnotationRotationMixin()](https://pdfjs.express/api/Core.Annotations.RotationUtils.html#RectangularCustomAnnotationRotationMixin__anchor)
- [UI - dangerouslySetNoteTransformFunction(noteTransformFunction)](https://pdfjs.express/api/UI.html#.dangerouslySetNoteTransformFunction__anchor)

Forums:
- [License key is not recognized in production](https://pdfjs.community/t/license-key-is-not-recognized-in-production/1301/1)
- [Licence key not working with version 8.2](https://pdfjs.community/t/licence-key-not-working-with-version-8-2/1310/1)
- [Is it possible to hide authentication key GET api from network?](https://pdfjs.community/t/is-it-possible-to-hide-authentication-key-get-api-from-network/562/1)

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