When Google Analytics GA4 only shows ‘(not set)’ as the traffic source, it is a common and frustrating issue. GA4 displays ‘(not set)’ when it cannot attribute source information to a session. Therefore, it is important to understand the causes and fix them specifically. In this guide to the GA4 (not set) problem, we explain the background and solutions. We show how you can significantly reduce the share of ‘(not set)’ entries.

Why Do I Only See ‘(not set)’ as Traffic Source in GA4?

GA4 shows ‘(not set)’ when it cannot determine the source of a session. This frequently happens with direct traffic where no referrer information is transmitted. However, missing or incorrect UTM parameters can also be the cause. Furthermore, cross-domain tracking issues lead to ‘(not set)’ entries. Therefore, also check whether your UTM parameters are correctly recognized. Incorrect UTM tags are one of the main causes of this problem.

How to Reduce the ‘(not set)’ Share in GA4

There are several measures to reduce the share of ‘(not set)’ in your GA4 reports. Consistently use UTM parameters for all paid and newsletter campaigns. Additionally, set up cross-domain tracking if users switch between multiple domains. The GA4 guide to cross-domain tracking helps with this. Server-side tagging also reduces the ‘(not set)’ share as referrer data is captured more reliably.

Our Recommendation

Consistently use UTM parameters for all external campaigns with uniform lowercase naming. Set up cross-domain tracking if your website spans multiple domains. Additionally, enable Consent Mode v2 so GA4 can capture source data even without cookie consent. A ‘(not set)’ share below 10 percent is a good target for most websites.

Conclusion

The ‘(not set)’ share in GA4 can be significantly reduced through consistent UTM tagging and cross-domain tracking. A certain share is unavoidable since direct traffic provides no source data. Our SEO agency helps you improve your GA4 data quality. Also read our post about missing organic keywords in GA4.