Azure OpenAI in Sweden Central: all deployments return DeploymentNotFound, management changes time out (case 2609290050003807)

Problem description

Since 28 Sep 2026 around 23:00 UTC, every Azure OpenAI deployment on our subscription in Sweden Central fails. The portal and the CLI still show all deployments as Succeeded, but every call returns 404 DeploymentNotFound on /openai/deployments/*, 500 on /openai/v1/chat/completions, and "Gateway cannot authenticate upstream services" on the services.ai.azure.com models endpoint. Changes fail too: changing a deployment's capacity ends in GatewayTimeout after two minutes, and the resource then stays locked for about an hour.

Environment

Azure AI Foundry / Azure OpenAI, Sweden Central, four resources on the same subscription, all affected. Models gpt-5.6-terra, gpt-5.6-luna and gpt-5.6-sol (EU Data Zone Standard), among others. Endpoints *.openai.azure.com, *.cognitiveservices.azure.com and *.services.ai.azure.com.

What I've already tried

I confirmed in the portal and the CLI that all deployments show Succeeded. I tested the same models on our resources in Germany West Central, Poland Central, France Central and West Europe, and they all work. The Azure status page shows no incident. I tried to lower the capacity of the Sweden deployments to free their quota, but every attempt timed out. I moved production to Global Standard deployments in Germany as a stopgap and filed an EU Data Zone quota increase request. Request IDs and activity log correlation IDs for each error are in support case 2609290050003807.

Current status

Still broken. The Sweden deployments hold our entire EU Data Zone quota for the three gpt-5.6 models, so we cannot create EU Data Zone deployments in any other region either. Our data processing agreements require EU-only processing, so Global Standard is only a temporary workaround. I need someone from the Azure OpenAI team to either repair the Sweden Central resources or release the Data Zone quota they hold.