Copy Data from Blob in data pipeline occurring Failed to load

[QuintinC_HKG]

HI experts,

I am trying to instead my data platform with Microsoft Fabric. I was setup vNet data gateway and checked vNDG online and tested connectivity to Blob.

Blob was setup PE in A subnet and vNDG located B subnet. There is Secured vHub and force routing to AzFW. AzFW Policy allowed vNDG HTTPS access to '*.blob.core.windows.net' in application rules. Checked logs of AzFW show traffic was passed to PE and logs of Blob show vNDG sussccess to communicate Blob.

But I can't browse blob in the copy data activity.

Click test connection in properties of copy data it shows

May I know how to troubleshoot it? Can any tools view logs following Activity ID?

[QuintinC_HKG]

Hi @v-veshwara-msft 

sorry late reply. since I had another important job need to complete. I will update status of this case next week.

thank you for your assistance.

[v-veshwara-msft]

Hi @QuintinC_HKG ,

Just checking in to see if you query is resolved and if any responses were helpful.
Otherwise, feel free to reach out for further assistance.

Thank you.

[QuintinC_HKG]

I don't know how to test connectivity from vNDG VM but I tested vNDG connectivity on Fabric Portal. it is show normal.

and then my Fabric Capacity is using F8 SKU

Does this mean I need to create a VM in a subnet to test DNS resolution?

[v-veshwara-msft]

Hi @QuintinC_HKG ,
Thanks for the follow up.

Since your Fabric capacity is on F8 SKU, it is supported for use with VNet Data Gateway. The connectivity check in the Fabric portal shows only the gateway status, but for DNS resolution you need to validate it from within the same subnet (or vNet) as the VNet Data Gateway.

The common way to do this is by using a VM in that subnet and running Powershell commands like:

• nslookup <yourstorageaccount>.blob.core.windows.net --> should return the private IP of the storage account’s private endpoint

• Test-NetConnection <yourstorageaccount>.blob.core.windows.net -Port 443 --> validates both DNS resolution and TCP connectivity

If you already have a VM in that subnet or in a correctly peered vNet with proper DNS configuration, you can use that instead of creating a new VM. If no such VM exists, then creating one is the simplest way to run these checks.

Hope this helps. Please reach out for further assistance.

Thank you.

[v-veshwara-msft]

Hi @QuintinC_HKG ,
Just wanted to check if the response provided was helpful. If further assistance is needed, please reach out.
Thank you.

[v-veshwara-msft]

Hi @QuintinC_HKG ,

Thanks for  reaching out to Microsoft Fabric Community and sharing the details and screenshots.

The error code WebRequestTimeout with the message “A task was canceled” usually indicates that the connection from Fabric through the VNet Data Gateway is not completing within the required time window, even though firewall and Blob logs show allowed traffic. Since the storage account is configured with a private endpoint, please review the following:

1. Ensure DNS resolution for the private endpoint is working correctly inside the subnet where the gateway is deployed. The blob FQDN should resolve to the private IP.

2. Confirm that the Azure Firewall policy is not only allowing *.blob.core.windows.net public endpoints but also correctly resolving to the private endpoint FQDN.

3. Test connectivity from the VNet Data Gateway VM with nslookup and Test-NetConnection to verify it can reach the private endpoint IP.

4. Check that your Fabric capacity SKU is supported. VNet Data Gateway is currently available for P, F, and A4 or higher (A4, A5, A6, A7) SKUs. For F SKUs, F8 and above are recommended, although all F SKUs work.

VNet Data Gateway support for pipelines (Copy, Lookup, and GetMetadata activities) is still in public preview as announced at FabCon US in March 2025, with GA expected by end of September 2025. Because this is preview, some limitations or instability are possible.

Microsoft Fabric Roadmap

As a workaround, switching to the public endpoint and using the on-premises data gateway instead of the VNet Data Gateway could result in success. Another option is to use Dataflow Gen2, which already has stable support for VNet Data Gateway, if that fits your scenario.

Use VNet data gateways with Dataflow Gen2 in Fabric | Microsoft Learn

Similar community discussions that may be useful:

• Solved: Connect Blob storage to Microsoft Fabric. (Vnet Ga... - Microsoft Fabric Community

• Authentication Error on Private Endpoint for Blob Storage - Microsoft Q&A

• Solved: Re: Fabric to Azure blob storage account connectiv... - Microsoft Fabric Community

Hope this helps. Please reach out for further assistance.

Thank you.