[Poland Central] Azure OpenAI Vector Stores stopped working since Nov 10 – 404 "Workspace not found"

Hello,

Since November 10, 2026, all Vector Store management operations (listing, creating, and attaching files) for our Azure OpenAI resource deployed in the Poland Central region have stopped working. We use Vector Stores in conjunction with the Responses API (file_search).

Observations:

• Existing Vector Stores still works: Assistants/applications querying previously created Vector Stores via the Responses API (file_search) continue to retrieve data and respond normally. Only the control plane/management operations (list, create, attach files) are broken.
• Other regions are unaffected?: The exact same management setup and API calls work without any issues in other regions (e.g., France Central).

Symptoms (Poland Central management operations only):

• Microsoft Foundry Portal: Navigating to Assistant Vector Stores fails to load existing vector stores and throws a 404 error. Attempting to create a new vector store via the UI fails with: Failed to create vector store. Request failed with status code 404.

• REST API: Calling POST /openai/v1/vector_stores (as well as listing or attaching files) returns an HTTP 404 Not Found error with the following payload:

JSON

{
  "error": {
    "code": "not_found",
    "message": "Workspace not found. [Request ID: 291afa1ed54e6966cf064b42d66b6115]",
    "type": "error",
    "details": [],
    "additionalInfo": {
      "request_id": "291afa1ed54e6966cf064b42d66b6115"
    }
  }
  

My question:

Is there an ongoing service degradation, control-plane routing issue, or recent backend API change in Poland Central causing /openai/v1/vector_stores management endpoints to return "Workspace not found" (while existing stores still succeed) — and how can we restore Vector Store management capabilities for our existing resource? Any guidance, known workarounds, or advice on how to mitigate or recover from this outage while staying on Azure OpenAI would be greatly appreciated.