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Microsoft Fabric Error:
InputValidationError

What does this error mean?

A Fabric pipeline or Mirroring activity received data that failed input validation — most commonly because a required field is missing, a value is out of the allowed range, or the on-premises data gateway (OPDG) endpoint configuration is invalid or unreachable.

Common causes

  • 1The on-premises data gateway service is stopped or not running on the gateway machine
  • 2Network connectivity between Fabric and the gateway endpoint is blocked (firewall, proxy, or VPN)
  • 3The gateway was registered under a different tenant or user account than the one used for mirroring
  • 4The gateway machine's outbound internet access to Azure Service Bus is restricted
  • 5Gateway version is outdated and no longer supported by the Fabric service

How to fix it

  1. 1Open the failed pipeline run in Fabric Monitor and read the full error detail — the message identifies the specific field or validation rule that failed.
  2. 2If the error references a gateway endpoint, verify the on-premises data gateway (OPDG) service is running on the host machine and the gateway status shows as Online in the Fabric portal.
  3. 3Confirm the linked service or connection configuration matches the expected input schema — check required fields are populated and values are within valid ranges.
  4. 4Restart the gateway service on the OPDG host if the gateway appears offline: go to Services.msc on the gateway machine and restart the 'On-premises data gateway' service.
  5. 5For persistent validation errors, consult the OPDG troubleshooting guide: https://learn.microsoft.com/en-us/data-integration/gateway/service-gateway-tshoot.

Beyond the docs

Common practitioner solutions not covered in the official documentation.

  1. 1Open the On-premises Data Gateway app on the gateway machine and verify the service is running and showing 'Online'
  2. 2Check that the gateway machine can reach the required Azure Service Bus endpoints (*.servicebus.windows.net on port 443 or 5671)
  3. 3Review the gateway diagnostic logs for specific connection errors (available in the Gateway app under Diagnostics)
  4. 4Ensure the gateway is registered under the same tenant as the Fabric workspace used for mirroring
  5. 5Update the gateway to the latest version if it is outdated

Frequently asked questions

Does this error affect all datasets using the same gateway?

Yes — all datasets routed through the affected gateway will fail simultaneously. Resolving the gateway configuration or credential issue restores all of them at once.

Does this error appear in Power BI Desktop?

No — Fabric items are cloud-native. Desktop can connect to Fabric semantic models but cannot trigger or observe Fabric-specific errors.

Can this error resolve itself without intervention?

No — gateway errors require manual action: re-entering credentials, restarting the gateway service, or correcting the network path between the gateway and the data source.

How long does it take to fix?

A simple credential refresh takes 5–10 minutes. Network or firewall issues can take 30–120 minutes depending on your infrastructure access.

Source · learn.microsoft.com/en-us/fabric/mirroring/sql-server-troubleshoot

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