How to fix this error Value cannot be null.\r\nParameter name: s", azure stream analytics

The error message "Value cannot be null. Parameter name: s" typically indicates that there is an issue with one of the parameters being passed to a function or method in Azure Stream Analytics, which is likely related to the configuration of your datasets. Since you mentioned that the issue arises when you try to onboard a 7th dataset, it could be related to a limit on the number of datasets or connections that can be handled simultaneously.

In your case, it seems that deleting one of the existing datasets allowed you to onboard a new one successfully. This suggests that there may be a restriction on the maximum number of datasets you can have in your streaming job at one time. To resolve this issue, you can consider the following steps:

1. Check the Limits: Verify if there are any documented limits on the number of datasets or inputs that can be configured in your Azure Stream Analytics job.
2. Review Dataset Configuration: Ensure that all datasets are properly configured and that none of them are missing required parameters.
3. Monitor Resource Usage: Check the resource usage and performance metrics of your Azure Stream Analytics job to ensure it is not hitting any resource limits.

If the problem persists after checking these aspects, you may want to reach out to Azure support for further assistance.

References:

• Azure Stream Analytics data errors
• Troubleshoot input connections

Hi @Naveen S Kumar Thanks for describing your issue in detail. It's unusual to encounter this error only when adding a 7th dataset to your Azure Stream Analytics job.

The error message:

Value cannot be null.
Parameter name: s

is a .NET-level exception, and in the context of Azure Stream Analytics, it typically points to a missing or improperly configured string parameter — often something like an input alias, name, or configuration value being set to null.

Based on your description, here’s what stands out:

• You can onboard up to 6 datasets without issue.
• Adding a 7th dataset (regardless of which one) results in a failure.
• Removing an existing dataset and adding a new one works — confirming the issue isn’t with the dataset content but with the job’s configuration or internal limits.

Possible Cause

This usually happens when one of the following parameters such as name, alias, or a required configuration is missing, empty, or null during the creation of the input. The Stream Analytics backend expects a valid string and throws this error when it receives null.

It’s also possible you’re hitting a soft limit or internal resource constraint related to job complexity or metadata handling when adding more inputs.

Suggested Fixes

1. Check the 7th dataset input configuration: Ensure the name or alias is not empty and follows naming conventions (alphanumeric, no special characters, no spaces). Avoid copy-pasting from existing inputs without renaming.
2. Review the input JSON definition: If using the Azure Portal: Open the input in JSON view and check for any null or missing values. If using ARM templates or CLI: Make sure each input’s "name" and "properties" fields are correctly populated.
3. Test with a simplified input: Try adding a new 7th input with a minimal configuration and a simple name. Don’t reference it in the query yet just see if it saves and the job starts.
4. Check Stream Analytics job limits: There are documented limits on: Number of inputs, Query complexity, Streaming Unit (SU) capacity. If needed, scale up the job to increase capacity.
   You can review limits here: Azure Stream Analytics Limits

Hope this helps. Do let us know if you any further queries.

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