Non-attributed calls

In some reports you may notice calls that are listed as coming from an unknown source. These are calls that Nimbata was not able to attribute to a tracked marketing source or session.

When this happens, it means Nimbata did not have a source tag (such as UTM data or dynamic source information) available for that particular call. This classification describes the result of attribution, not the cause. Multiple scenarios can lead to a call being marked as unknown source.

In many cases, this occurs when a caller dials the tracking number directly, for example by manually entering the number, calling from a list or brochure, or using the number outside of a tracked environment. However, unknown source calls can also occur when attribution data is unavailable at the time the call is placed.

What to check

The following checks can help you understand why calls are not being attributed to a specific source.

If you see calls with an unknown source:

• Verify how the number is being displayed:

Make sure your tracking numbers are only shown dynamically via your website or tagged materials where source data can be captured. If the number appears elsewhere (printed materials, saved in a contact list, shared outside tracked pages), callers may dial it directly and no source information will be sent.

• Review your dynamic number insertion setup:

If you expect more calls to be attributed to tracked channels (UTM tags, campaign links, ad sources), confirm that your dynamic number insertion (DNI) script is installed correctly on the pages you want to track. Incorrect or incomplete DNI setup can result in calls without source attribution.

Calls with unknown source do not necessarily indicate a problem with your tracking numbers; they reflect calls that could not be mapped to a known marketing source based on how the call originated.

If you’re seeing a higher-than-expected number of unknown source calls, reviewing how and where your tracking numbers are displayed is a good first step.

Updated on: 16/02/2026