Failed to Create Rule When Adding Azure Blob Storage Event Trigger in Microsoft Fabric Pipeline

From my experience, your biggest blocker is likely region alignment between Fabric capacity, storage account, and resource group. Event Grid validation webhooks tend to fail when they cross regions unnecessarily, and Fabric trial capacity makes this more sensitive.

Here is what I suspect and recommend:

Region Mismatch

• Your Fabric capacity is in Japan West
• Your Azure Blob Storage is also in Japan West
• But your Azure subscription and resource group is in US East

Even though the storage account is in Japan West, having the subscription’s resource group in another region can cause cross-region Event Grid handshake problems, especially for services like Fabric pipelines that require low-latency Event Grid webhook confirmation.

Recommendation:
Create a resource group in Japan West and move or recreate your storage account there. Event Grid works best when Fabric capacity, resource group, and storage account are in the same region.

Fabric Trial Capacity Limitations

Fabric Trial capacity sometimes restricts:

• Certain cross-region Event Grid triggers.
• Persistent event subscription handshakes (esp. when “secure webhook” verification is needed).

If possible, try on an F64 or higher paid capacity in the same region as the storage account to confirm if it is a trial limitation.

Event Grid Permissions

You already have:

• EventGrid Contributor
• EventGrid EventSubscription Contributor
• Storage Blob Data Owner

However, Fabric’s Event Grid integration also requires that:

• The Fabric service principal has Microsoft.EventGrid/eventSubscriptions/* permissions on the storage account.
• The subscription-level EventGrid Contributor role is applied directly, not just inherited via groups.

Check Azure > IAM on the Storage Account and make sure these roles are explicitly assigned.

Network / Firewall

Even though you said “no specific network restrictions”, double-check that:

• The storage account firewall allows “Allow Azure services on the trusted services list to access this storage account”.
• Fabric’s public IPs for Japan West are allowed if you have any custom firewall settings.

Manual Workaround

If the rule creation from Fabric keeps failing:

1. Manually create the Event Grid subscription in Azure Portal, with destination pointing to a Webhook endpoint you control.
2. Then connect that endpoint to Fabric’s Eventstream via custom source. This avoids the auto-creation path that Fabric uses, which is where the failure is happening.