# System.Security.SecurityException:

**URL:** <https://forum.xltoolbox.net/t/system-security-securityexception/833>\
**Category:** bugs\
**Created:** [April 15, 2020, 2:11am UTC](https://forum.xltoolbox.net/t/system-security-securityexception/833 "2020-04-15T02:11:44Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Adlarosa](https://forum.xltoolbox.net/letter_avatar_proxy/v4/letter/a/73ab20/32.png) [@Adlarosa](https://forum.xltoolbox.net/u/Adlarosa)\
**Post date:** [April 15, 2020, 2:11am UTC](https://forum.xltoolbox.net/t/system-security-securityexception/833/1 "2020-04-15T02:11:45Z")

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Please help with this:

System.Security.SecurityException: The custom functionality of this application will not work because the certificate used to sign the XLToolboxForExcel implementation manifest or its location is not trusted. Please contact the administrator for assistance.

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<div class="post-metadata">

**Author:** ![system](https://forum.xltoolbox.net/uploads/default/original/1X/b39aeef1f68836c8cece0791714485f9a56b5d41.png) [@system](https://forum.xltoolbox.net/u/system)\
**Post date:** [September 2, 2024, 9:29am UTC](https://forum.xltoolbox.net/t/system-security-securityexception/833/2 "2024-09-02T09:29:17Z")

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