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New Azure OpenAI subscription returning 403 "unusual behavior" — is there a new-subscription warm-up / ramp period?

David 0 Reputation points
2026-05-27T16:08:23.02+00:00

We recently created a new Azure subscription and moved it into production to run load tests. We are seeing the error below on the new subscription, while our existing subscription handles the same workload without issue.

On the new subscription we sent roughly 220 million tokens / 17,000 requests through gpt-5-mini (Global Standard) before hitting the error:

403 - {'error': {'code': 'Forbidden', 'message': 'Your resource has been temporarily blocked because we detected unusual behavior.'}}

Our assumption is that a newly created subscription has some form of initial throttling or trust/warm-up period, since only the new one is affected and the workload is identical to what our existing subscription handles fine.

Questions:

  1. Can you confirm whether new subscriptions have a warm-up or ramp-up period for Azure OpenAI usage?
  2. If so, what does that window look like (duration, RPM/TPM thresholds), so we can cap usage during it?
  3. Is there a process to request a faster ramp or pre-approval for higher throughput on a new subscription?

We can throttle both RPM and TPM as needed. Happy to share the affected subscription ID privately if that helps with diagnosis.

Azure OpenAI in Foundry Models

2 answers

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  1. kagiyama yutaka 3,510 Reputation points
    2026-05-28T08:05:27.8066667+00:00

    I think Azure has no warm‑up for new subs, and the 403 is just the trust/safety block. you ease the pattern a bit and file the abuse/mitigation review.

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  2. Anshika Varshney 12,790 Reputation points Microsoft External Staff Moderator
    2026-05-28T05:58:42.44+00:00

    Hi @David

    Thank you for your patience. We received an update from the Product Group team and wanted to share the findings.

    The HTTP 403 error you are seeing with the message about unusual behavior is because your Azure OpenAI resource has been temporarily blocked by the platform’s abuse detection system. This is an intentional Trust and Safety action and not due to a service outage or platform bug.

    This kind of block can happen when the system detects patterns that look unusual, such as repeated requests, high frequency calls, or activity that may trigger safety or policy checks. From the platform side, this is expected behavior and is done to protect the service.

    At this stage, there is no configuration change or troubleshooting step that can unblock the resource directly from the service side. The correct way forward is to request a review through the abuse mitigation process.

    What you can do now is:

    • Submit an appeal through the Azure OpenAI abuse or mitigation request process
    • Provide your subscription details and resource name
    • Share a brief explanation of your usage scenario so the team can review and validate it

    Once submitted, the relevant team will review your case and take appropriate action if the block was applied in error.

    In short, this is not a technical issue in your setup but a safety enforcement action, and it requires review through the designated process.

    Please let me know if you need help.

    Please 'Upvote'(Thumbs-up) and 'Accept' as answer if the reply was helpful. This will be benefitting other community members who face the same issue.
    Thankyou!

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