DataFlow Gen2 Issue

Some changes were applied at the firewall level, but honestly, I don't think that was the root cause of the issue. When checking the error on the gateway, it showed a set of successful tests that included validating communication to the address specified in the original error:

'Please check your network connectivity to ensure your on-premises data gateway can access scu.frontend.clouddatahub.net and restart the service to retry the connection again once the connectivity issue has been resolved.'

In addition to this problem, I was also having issues using the Copy Data activity in the pipelines; in that case, it couldn't even reach the server. Interestingly, after some maintenance on the Azure firewall (my 'on-premises' server is actually hosted in Azure), the pipeline Copy Data activity started working.

However, as of today, the original error remains unresolved.Regarding Dataflow Gen2, I have ruled out server-side and gateway errors since I am able to successfully resolve the SQL query on the server side. The issue seems to be related to tenant or workspace configurations, as the error triggers specifically when trying to configure the Lakehouse as the data destination.

At this point, I have tried most of your recommendations, and the one that makes the most sense to me is the one from Prince0011​. However, I have validated the workspace identity, and it is configured correctly. That being said, I don't have the 'Azure connections' setting configured in the workspace. Since I don't have tenant-level privileges, I will try to get the administrator's assistance with this and will let you know how it goes.

HI LUISS252​,

Since the SQL Server source is working, reconfigure the Lakehouse destination, reauthenticate, and publish the Dataflow again, as recommended for destination validation exceptions. If the issue persists, check the destination availability, permissions, and recent changes. If a proxy is used with the gateway, review its configuration and ensure the gateway is up to date. If queries reference other queries or staged data, also verify outbound TCP 1433 connectivity from the gateway/proxy to the required Fabric endpoints.

On-premises and virtual network data gateway considerations for data destinations in Dataflow Gen2 …

Using an On-Premises Data Gateway in Power Platform Dataflows - Power Query | Microsoft Learn

Dataflow Gen2 data destinations validation rules - Microsoft Fabric | Microsoft Learn

Thank you.

Hi LUISS252​ 

From the error it appears that it is being closed from your source system or your SQL server. I'd recommend working with your SQL DBA to make sure that the connectivity is working as expected.

Hi,

Since Notebook writes work fine but Dataflow Gen2's Lakehouse destination doesn't, this usually comes down to workspace identity or staging permissions, not the Gateway itself.

Check that your workspace has a Workspace Identity enabled, Dataflow Gen2 destinations to Lakehouse rely on it for the write step, Notebooks don't need this the same way.

Also confirm the Dataflow's staging settings, if "Fast copy" or staging is enabled and misconfigured, Lakehouse destination writes can silently fail even when the source connection itself is fine.

If this helped, feel free to give it a kudos or mark it as solution, helps others find it too.

If your problem can't solve, please let me know 

LUISS252​ 

I wouldn't start by changing the Lakehouse permissions or recreating the Lakehouse.

The message doesn't indicate an authorization failure such as 401/403; instead, the connection itself is being closed unexpectedly.

Please check On Premises  Gateway connection, since your original sources is on prem SQL, so you need to make connection for that so you can dump the data in lakehouse.

2nd option, you might need to check is completely check firewall settings, some ports or internet traffic may be blocked.  which is causing the connection to break.

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