GA4 No Data: Causes and a Step-by-Step Check

Why does Google Analytics show no data?

When Google Analytics 4 (GA4) shows no data, it is usually due to one of a few causes: standard reports are not yet processed, the measurement ID does not match the data stream, the tag is not published in Google Tag Manager, a filter is blocking traffic, or visitors have not consented in the cookie banner. Less often, data thresholds, ad blockers, or a wrongly selected property are the issue. You can check these in a fixed order without needing a developer.

First, distinguish whether no data is arriving or just too little. If no data arrives, the implementation is likely broken. If there is too little data, it is likely due to consent, filters, or thresholds. This distinction saves time, as you only need to check a subset of possible causes.

Step 1: Check real-time instead of standard reports

GA4 processes data for standard reports and explorations with a delay. According to Google Help, processing can take 24 to 48 hours, and daily data is usually available after about 12 hours in standard properties. If you check the "Traffic acquisition" report on the day of setup and see nothing, it is not necessarily an error. The real-time report, however, shows user activity from the last 30 minutes. Open your website in a second window, consent in the cookie banner, and click two or three pages. If you appear in the real-time report shortly after, the basic measurement is working. You just need to wait.

If the real-time report also stays empty, no requests are reaching GA4. The next steps address this case. First, check if you have selected the correct property in the top left. Agencies with many client accounts often end up in an old property or a test environment that is no longer used.

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Step 2: Match measurement ID and data stream

Every web data stream in GA4 has a measurement ID that starts with G-. You will find it in Admin under Data streams. This exact ID must be in the Google tag in your Google Tag Manager container or, if the site works without Google Tag Manager, in the embedded code. A swapped letter, an ID from an old property or the old UA number from Universal Analytics is enough for the data to end up in the wrong place or nowhere at all.

In the data stream details, GA4 also shows if data was received in the last 48 hours. If it indicates no data is arriving, the connection between the website and the stream is broken. Also check if the domain in the stream matches the live website. This is not a hard filter, but it helps you spot mix-ups between the live site and a test site.

Step 3: Is the tag published and loading?

A classic: everything is set up correctly in Google Tag Manager and the tag works perfectly in preview mode, but nobody clicked ‘Submit’. Preview mode only shows you what would happen. Normal visitors only get the published version. Under Versions in Google Tag Manager, check when the container was last published and whether your change is included.

Next, check in the browser whether the site actually sends requests to Google Analytics. Open the developer tools, switch to the Network tab and filter for ‘collect’. After you consent in the banner, requests with your measurement ID should appear there. If you see nothing, either the container is not loading, the Google tag has no matching trigger, or an ad blocker in your browser is blocking the requests. So always test in a browser profile without extensions as well.

• Container code is missing from the source after a theme change or relaunch.
• Google tag is attached to a trigger that never fires, such as a wrong page path.
• The tag waits for a consent signal that the banner never reports to Google Tag Manager.
• A caching plugin serves an old version of the page without the container.
• The ad blocker in your own browser blocks the requests only for you.

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Step 4: Filters, internal traffic, and data thresholds

If data arrives but there is noticeably little of it, look at the data filters. In GA4 you can exclude internal traffic and developer traffic. If the IP range for the office was defined too broadly, for example because of a typo in the rule, real visitors are suddenly excluded too. Data filters also only apply to new data and cannot be reversed retroactively. So set a suspicious filter to ‘Testing’; you can then compare in the reports how many hits it would mark.

Data thresholds are another cause of missing rows. For small numbers, GA4 withholds values if they could otherwise allow conclusions about individual people, especially when Google signals is active or demographic data is in the report. You can tell from a notice at the top of the report. In this case the data is not really missing, it is just not displayed. A longer date range or the device-based reporting identity often helps.

Step 5: Understand consent and Consent Mode

With a cookie banner, GA4 only fully measures visitors who consent. Those who reject do not appear as standard sessions. This is intended and not an error. It becomes problematic if nothing arrives even after consent. Then the banner is not reporting the decision correctly to Google Tag Manager, or the Google tag is waiting for an event that never comes. Test this by consenting in the banner and checking the Network tab to see if requests start.

With Google Consent Mode v2 in advanced mode, the site sends cookieless signals even without consent. Google can use them to model gaps in the reports. According to Google Help, this modelling requires, among other things, at least 1,000 events per day without consent on at least 7 days, and at least 1,000 users per day with consent on at least 7 of the last 28 days. The reporting identity must also be set to ‘Blended’. Many small websites do not reach these volumes. If Consent Mode runs only in basic mode, no signals at all are sent without consent. Either way, some visitors are permanently missing. What matters is that you know this and do not mistake it for a technical error. This article is not legal advice. Clarify which variant suits your site with your data protection officer.

Real-world example: a roofing firm after a relaunch

A roofing firm has its website redesigned. The agency builds the new theme, carries over the texts and images and puts the site live. Two weeks later, the owner notices that GA4 has shown hardly any visitors since the relaunch and the contact form no longer reports any enquiries. The real-time report stays empty. The check shows that the container code was in the header of the old theme but is missing from the new one. At the same time, the old banner was replaced by a new cookie banner plugin that does not pass consent on to Google Tag Manager.

The fix took less than an hour: put the container code back, configure the banner to report the decision to Consent Mode, test the form event in preview mode and publish. The two weeks without data are lost for good, though, because GA4 cannot record anything retroactively. That is exactly why it pays to take a quick look at the real-time report after every relaunch, theme change or plugin update.

The checklist to tick off, and who can help

If GA4 shows no data, always work in the same order: check the real-time report, confirm the property, match the measurement ID with the data stream, check publishing in Google Tag Manager, search the Network tab for collect requests, test with and without consent, set data filters to ‘Testing’ and only then think about thresholds. In this order you will find most errors before you ever need to dig deeper.

If you would rather not click through all this yourself: Trackum’s free check opens your site in a real browser, loads it three times (no click in the banner, after rejecting and after accepting) and shows you within two minutes which measurement services send data when and what is missing. Free and without sign-up. If the check finds errors, the repair for €79 plus VAT fixes all findings in your existing Google Tag Manager, tested and with a short report.