> For the complete documentation index, see [llms.txt](./llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](./unicore/error-list/failed-to-place-required-callback.md).

# Failed to place required callback

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**This problem can be solved using our** [**Security Tool**](/instruction/preparing-the-system/security-tool.md)
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