"Internal Error" when using SQL DB connection in Lookup/Copy Activity as guest user

[THuss]

Since I couldn't find it in the known issues and just stumbled upon it I thought I'd share.

When you're connected to Fabric as a guest user, create a SQL DB, create a connection to that SQL DB, and then try to use that connection in a data pipeline for a lookup or copy activity, you will be able to select the connection and a database, but when searching for table metadata it will fail with the very nondescript "Internal Error".

Exact same setup but connection created by a "native" user works as expected.

[Prince0011]

Thanks for sharing this finding—it could definitely save others some troubleshooting time.

Based on your description, this appears to be related to guest user permissions or a current Fabric limitation rather than an issue with the Lookup or Copy activity itself. The fact that the same SQL Database connection works correctly when created by a native tenant user, but returns an "Internal Error" only for guest users, points to a service-side authentication or authorization issue.

A few suggestions:

• Verify that the guest account has all required permissions on both the Fabric workspace and the SQL Database.

• Test by recreating the connection using a native tenant account (as you've already done) to confirm the behavior.

• If the issue persists consistently for guest users, consider opening a Microsoft Support ticket, as this may be an undocumented product limitation or bug.

If you receive confirmation from Microsoft or discover a workaround, please share it here to help others experiencing the same issue.

If you found this reply helpful, please consider giving it a Kudos. If it helps resolve your question, marking it as the Accepted Solution will make it easier for other community members to find.

[Chanty4u]

Have a native tenant user:

Create the SQL connection

Or re-save the pipeline once the connection exists

Guest users can then:

Use the pipeline

Trigger runs

Modify logic (sometimes)

[Murtaza_Ghafoor]

I would say this is guest user a/c limitation rather than know issue with Microsoft fabric.
Specific permission or authentication limitation related to fabric guest account.

To validate this further kindly try from regular a/c and then update us if the same problem persist. Thanks

[v-karpurapud]

Hi @THuss 

We really appreciate you taking the time to post this! Your explanation of this behaviour will definitely help users who run into similar use cases. But just for clarity, this space is primarily focused on answering specific questions, while detailed write-ups like yours are best shared on the Fabric community blogs - Microsoft Fabric Community where they’ll get even more visibility and engagement.

Regards,

Microsoft Fabric Community Support Team.