Hi @Nathanael de Swardt ,
Thanks for reaching out to Microsoft Q&A.
To fix Azure Cognitive Search not returning results and vector search errors, first check your index schema and ensure the vector field is correctly defined. A common error, "Please assign a proper column/field for vector search. It should be of type Collection(Edm.Single)", usually means the vector field is missing or not set right. Go to your Azure Cognitive Search service, open the index, and verify if the vector field exists and is set as Collection(Edm.Single). Update the schema if needed. Supported Data Types in Azure Search for correct field setup.
If you see the "PermissionDenied: Principal does not have access to API/Operation" error when creating a vector index, it means you lack permissions. Head to Azure Cognitive Search → Access Control (IAM) → Role Assignments, and ensure your user, service principal, or managed identity has the Cognitive Services Contributor or Cognitive Search Contributor role. Add permissions if needed, then try again. More details are at Azure Q&A Permissions Error.
If your index returns no results when queried via the Azure Search Explorer, it might be due to failed document processing or improper data indexing. Go to Azure Cognitive Search → Indexes → Your Index, check the document count, and ensure records are there. If no documents are found, re-upload your data using the Azure portal, SDKs, or REST APIs, and set an appropriate embedding model when setting up the vector index. Azure AI Search Indexing.
After indexing, make sure queries are correctly formatted. In the Azure Search Explorer, test a broad query like { "search": "*" } to check for results. If no results are found, confirm your AI Search index is connected to the Azure AI Foundry chat. A query syntax guide is available at Azure Search Query Syntax. If the issue persists, check logs in Azure Cognitive Search → Monitoring → Diagnostic Settings to identify potential problems.
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