Why "utm_source" Shows as ‘o’ in Google Ads & How to Fix It

Introduction

Running paid ads without accurate tracking is like driving with your eyes closed. If you’ve spotted utm_source=o in Google Analytics or HubSpot, you're not alone. Many marketers face this strange tracking issue after setting up their Google Ads campaigns. This blog will walk you through why this happens, what’s causing it, and exactly how to fix it — so your reporting is clean and your decisions are data-driven.

What Does utm_source=o Mean in Your Reports?

If your analytics reports show traffic with utm_source=o, it means the source is not being tracked properly. Instead of showing “google” or another expected value, it's being replaced with the letter “o”, indicating a misconfigured or broken UTM structure.

This typically leads to:

• Misattribution of traffic

• Skewed reports in GA4 or HubSpot

• Poor campaign performance analysis

The Root Cause: Broken or Unsupported URL Parameters

Most often, this error is caused by:

• Unsupported dynamic parameters like {campaign_name} being used in the final URL.

• Incorrect UTM formatting, such as missing ampersands (&) between parameters.

• Empty or malformed values being inserted into dynamic placeholders.

When this happens, the UTM chain can break, and tools like Google Analytics fail to parse it correctly—leading to fallback or corrupted values like "o".

Why {campaign_name} Causes This Problem in Google Ads

A common mistake is using {campaign_name} in the tracking template or final URL like this:

...?utm_campaign={campaign_name}

❌ The problem?
{campaign_name} is not a supported Google Ads ValueTrack parameter, so it’s not replaced with anything—resulting in a broken string that leads to incorrect utm_source or utm_campaign values.

Instead, use:

• {campaignid} — the supported dynamic placeholder for campaign ID

• Or, a static, readable campaign name (e.g., utm_campaign=summer_sale_2025)

How to Properly Structure Your Google Ads Tracking Template

To ensure proper UTM tracking, use the Tracking Template field in Google Ads (not the final URL) and follow this format:

{lpurl}?utm_source=google&utm_medium=cpc&utm_campaign={campaignid}&utm_term={keyword}&utm_content={creative}&gclid={gclid}&hsa_acc={accountid}&hsa_ad={ad_id}&hsa_grp={adgroupid}&device={device}&hsa_mt={matchtype}&hsa_src={network}&hsa_tgt={targetid}

Replace {campaignid} with a static name if you prefer readable campaign labels.

Final URL: Should remain clean — just https://yourdomain.com/

Full Working Example of a Correct UTM Tracking Template

Let’s say you're promoting a campaign called "14YearsSale". Here’s what a fixed tracking setup would look like:

Final URL:

https://yourdomain.com/

Tracking Template:

{lpurl}?utm_source=google&utm_medium=cpc&utm_campaign=14YearsSale&utm_term={keyword}&utm_content={creative}&gclid={gclid}

This ensures all UTM values are correctly parsed by Google Analytics and HubSpot.

How to Check and Test UTM Values Before Going Live

Before launching your campaigns:

• Use Google Tag Assistant Chrome Extension to verify URL parameters.

• Test with GA4 Realtime to see if traffic is being attributed correctly.

• Paste your final URL with UTM values into the browser and check:

  • Are all parameters there?

  • Are values showing up correctly in Analytics?

Final Recommendations for Clean Google Ads Tracking

• ✅ Use only supported dynamic parameters (like {campaignid}, {keyword}, {creative}).

• ✅ Avoid using {campaign_name} or any unsupported tag.

• ✅ Keep the Final URL clean and move tracking into the Tracking Template field.

• ✅ Don’t mix manual UTM tagging with auto-tagging unless you fully understand the implications.

• ✅ Always test before going live.

Need Help Fixing UTM Issues or Running High-Performance Google Ads?

RW Infotech specializes in building, optimizing, and scaling Google Ads campaigns with precision. Whether you're dealing with tracking errors, low ROAS, or misfiring analytics, we can help you clean up your data and drive real results.

👉 Contact RW Infotech today to audit or set up your Google Ads tracking the right way:
🔗 www.rwit.io/contact