If fewer calls than expected are showing source, medium, or campaign data in GA4, you have one of two problems:

Capture gap

• Nimbata swapped the number but couldn't read the visitor's session data.
• Usually a cookie consent manager.

Integration gap

• Nimbata captured full session data, but it never reached GA4.
• Usually a Client ID or workflow misconfiguration.

They look the same on the surface but require different fixes.

Diagnose which one you have first.

Step 1. Check Nimbata's attribution data

• Go to Activity > Calls.
• Open an unattributed call.
• Check the Attribution section of the call record.

Source and medium are populated > data was captured but didn't reach GA4.

This is an integration gap. Go to Section A.

Source and medium are empty > session data was never captured.

This is a capture gap. Go to Section B.

Section A. Integration gap: call data not reaching GA4

A1. Verify your GA4 credentials

• Go to Integrations > Google Analytics in Nimbata.
• Confirm the Measurement ID (format: G-XXXXXXXXXX) matches exactly the one in GA4 under Admin > Data collection and modification > Data streams > [your stream] > Stream details.
• Confirm the API secret comes from Measurement Protocol API secrets on that same screen; not a Tag Manager token or any other credential.
• Confirm the integration status shows running in 1 workflow.

A2. Check whether the Google Client ID is being transmitted

Nimbata links call events to GA4 sessions using the visitor's _ga cookie.

If it isn't captured at call time, GA4 can't match the event to a session; even if source and medium are correct in Nimbata.

• In a call record, check for a Client ID field in the attribution data.
• If it's blank on calls that do have source and medium, the Client ID handshake is broken.

Common causes: the Nimbata script loads before GA4's gtag.js initializes, the _ga cookie is blocked by a consent manager, or a GTM error is preventing the GA4 tag from firing.

Fix: in GTM, set your GA4 configuration tag to fire on All Pages with no conditions, and ensure the Nimbata tag fires after it.

A3. Check your workflow configuration

• Go to Workflows.
• Open the workflow driving your GA4 integration.
• Trigger: must be set to Call ends, not Call starts.
• At call start, duration is 0; any duration filter will fail.
• Filters: check every condition.
• A common silent blocker is Recording = Yes.
• If a caller presses the privacy opt-out digit, recording stops and this filter fails.
• Replace it with Duration > X seconds instead.
• Status: Confirm the workflow is enabled and showing as running.

A4. Check for GA4-side data filters

• In GA4, go to Admin > Data filters.
• Confirm no filter is excluding events sent via the Measurement Protocol.

Section B. Capture gap: session data missing at the point of the call

B1. Check whether a consent manager is blocking the script

This is the most common cause, especially in markets with low opt-in rates (Germany, Sweden, France, Poland).

The pattern: DNI is working and numbers swap when tested, but a high percentage of calls from a specific market show no attribution.

To confirm:

• Open the affected site in a fresh browser session without accepting the cookie banner.
• Call the tracking number and check the resulting call record in Nimbata.
• If source and medium are blank, repeat the test after accepting cookies.
• If attribution appears after accepting, the consent manager is the cause.

Fix: review how your consent manager categorizes the Nimbata script and GA4 tag.

If compliant with your privacy policy, moving Nimbata to a Functional or Necessary category will resolve this.

Ensure the GA4 tag fires before Nimbata even in consent-pending mode, so the _ga cookie is set first.

B2. Check the script load order

Even without a consent manager, if Nimbata fires before GA4 it cannot read the _ga cookie.

• Open F12 > Network.
• Reload the page.
• Confirm the GA4 tag fires before the Nimbata script.
• In GTM, add a trigger dependency or sequence the Nimbata tag after GA4.
• In manual installs, place the Nimbata script tag below the GA4 tag.

B3. Check that your swap group source matches your traffic

• A Google Ads swap group only swaps for visitors with a gclid parameter.
• Calls from other channels won't have campaign attribution.
• An All Visitors swap group swaps for everyone but will show many calls as direct or organic.

Confirm your swap group sources match your attribution expectations.

Realistic attribution benchmarks

• 60-80% is typical for single-market setups with moderate consent rates.
• Below 50% usually indicates a fixable technical issue covered in this guide.
• Near 0% in one market with a working setup elsewhere is almost always a consent manager or script load order issue.

Detailed Guide: Google Analytics 4 integration: how to set it up in Nimbata

Detailed Guide: Google Ads conversions via GA4: how to import Nimbata call events

Detailed Guide: How to set up your first workflow

Troubleshooting: Tracking number not swapping: full troubleshooting guide

Updated on: 07/04/2026