An Apache Spark-based analytics platform optimized for Azure.
There is no self-service switch that enables storage-optimized AI Search endpoints. The documented workspace prerequisites are Unity Catalog and serverless compute, but storage-optimized endpoints also exclude workspaces using customer-managed keys and FedRAMP-compliant workspaces.
Because Standard endpoint creation succeeds, your general AI Search permissions and API syntax are working. The rejection occurs before provisioning and is therefore a workspace eligibility decision, not a CLI or REST issue.
Check both workspaces for customer-managed keys and any applicable compliance profile. If neither limitation applies, the next step is Databricks support or your Databricks account team. Ask them to verify storage-optimized endpoint entitlement and control-plane availability for each workspace ID. Include both workspace IDs, Azure regions, the complete API response, timestamp, and request ID.
Region support for Azure Databricks or AI Search generally does not guarantee that every endpoint type is enabled on every workspace/control-plane shard. Recreating the endpoint, changing the SDK, or granting additional workspace permissions will not bypass this check. Continue with Standard endpoints until Databricks confirms or enables eligibility.