Azure OpenAI Deployment: Error 715-123420 'Unusual Activity' Since October 2026

Problem description

Since 2026-10-14, every create or update of an Azure OpenAI model deployment (Microsoft.CognitiveServices/accounts/deployments) in one of our subscriptions is rejected with error 715-123420: "Our system has detected this request as unusual activity for your account. If you are confident this is in error, please contact support."

The portal diagnostics and the support assistant on the linked support request both concluded this is a subscription-level anti-abuse hold that cannot be cleared through self-service. I need a Microsoft engineer to review it. I can share the subscription, resource and correlation ids privately, through a private message or the linked support request.

Environment

• Region: West Europe
• Model: text-embedding-3-large, version 1, deployment type DataZoneStandard
• Deployment method: ARM template (Bicep), from CI through a federated (OIDC) service principal

What we've already ruled out

• The template: unchanged since the last successful deployment write, on 2026-10-12. It had deployed the same resources several times before.
• One specific resource: on 2026-10-20 a brand-new AI Services account in the same subscription was created fine (account, project and role assignments), and the 715 came back on its model deployment.
• The identity: it fails the same way through the CI service principal and through a user signed in interactively.
• Policy: a single audit-only policy assignment, unchanged since January.
• Quota, model availability, permissions, deprecation, service incidents: ruled out by the portal diagnostics.

We have stopped retrying, as advised, and are keeping the deployment definition unchanged.

Question

Can a Microsoft engineer review the anti-abuse hold on this subscription for Azure OpenAI model deployments and lift it, or tell us what we need to verify on our side?