Add guidance for cross-repository documentation issues

CONTRIBUTING.md

@@ -2,6 +2,14 @@
 
 Thank you for your interest in contributing to our documentation! We appreciate your feedback, edits, and additions to our docs. Please see the [Microsoft Learn documentation contributor guide](https://learn.microsoft.com/contribute/) for information on how to do quick edits, get a local contribution environment set up, review open pull requests, and create quality issues, along with some "Microsoft writing essentials", the Learn site authoring pack for VS Code, and info about Hacktoberfest.
 
+## Issues with other Microsoft documentation repositories
+
+If you encounter issues with contribution links or guidance in other Microsoft documentation repositories (such as broken authentication links), you can:
+
+- Use the [Microsoft Learn documentation contributor guide](https://learn.microsoft.com/contribute/) as an alternative resource for general contribution guidance
+- Report cross-repository issues in this repository if the target repository doesn't have Issues enabled
+- Check the [Microsoft Q&A platform](https://learn.microsoft.com/answers/) for community support
+
 ## Internal contributions
 
 If you are a Microsoft employee, please contribute through the [private content repository](https://github.com/microsoftdocs/windows-dev-docs-pr).