If Google Analytics 4 receives no data at all, the cause is usually technical: the measurement ID is wrong, the tag was never added to the page, or a change in Google Tag Manager wasn't published. If data arrives but far below reality, cookie consent (some visitors reject), ad blockers or a misconfigured internal traffic filter are most likely at work. The first check is always the same: open the site yourself and see whether you appear in GA4's Realtime report.
The distinction matters. 'No data' is a setup problem and is usually fixed within an hour. 'Missing data' is often a settings or expectations problem and partly permanent.
Realtime first
Open your site on your phone with Wi-Fi off. If a cookie notice appears, accept it and browse a few pages. In GA4, open the Realtime page under Reports. Within a minute you should see yourself in the users count for the last 30 minutes.
If you do, the setup works; skip to 'missing data' below. If you don't, check these in order.
If no data arrives
1. The measurement ID is wrong. In GA4, open your site's stream under Data streams in Admin; you'll see a measurement ID starting with G-. Is it identical, character for character, to the one on your site? Old Universal Analytics IDs (starting with UA-) no longer collect data. If a site set up years ago still carries a UA code, that's the problem.
2. The tag isn't on the page. Right-click the page, view the source and search for your measurement ID. If it's not there, the tag was never added, or it disappeared with a plugin update or theme change. Google's Tag Assistant shows which Google tags run on the page.
3. The Tag Manager change wasn't published. If you use Google Tag Manager (GTM), adding or editing a tag isn't enough; you have to publish a new version with the 'Submit' button at the top right. Unpublished changes only work in preview mode.
4. You're looking at the wrong property. If you have several GA4 accounts or properties, the one the tag sends to may differ from the one you're viewing. Choose the right property from the account picker at the top left.
5. Consent can never be given. If the tag loads only after consent and your cookie notice's 'Accept' button is broken, nobody is measured. Give consent in a private window and look for 'collect' requests in the Network tab of developer tools.
Data arrives but is incomplete
6. Cookie consent and Consent Mode. On a site that complies with KVKK and GDPR, analytics cookies don't load until the visitor consents. Visitors who reject or dismiss the notice don't appear in reports, or appear only as modelled estimates. That isn't a bug; it's the rule working. On Kodyva's own site, Google tags also load only after cookie consent, so GA4 figures should be read as a lower bound on real visitors. We explain how to set up a cookie notice in cookie notices and KVKK.
7. Ad blockers and browser protections. Ad-blocking extensions, browsers like Brave and some privacy settings block Google Analytics requests. Numbers drop depending on how much of your audience uses them.
8. An internal traffic filter excludes everyone. In GA4 you can define an IP rule to exclude internal traffic (visits from your own office) and activate the filter. If the rule is written wrongly (a very broad IP range, for example), real visitors are excluded too. Check active filters under Data filters in Admin.
'No data yesterday, there today': reporting delay
The Realtime report is instant, but standard reports can lag by up to 24 to 48 hours. On a newly created property, reports can look empty on the first day. Meanwhile, use Realtime and DebugView.
DebugView sits under Admin and shows events one by one when debugging is on, through Tag Manager's preview mode or a browser extension. This is where you test whether custom events like form submissions or WhatsApp clicks work.
Double counting: if numbers are too high
The opposite problem happens too. If the tag is added both in the theme settings and in Tag Manager, every page view is counted twice. Engagement rate looks oddly high and session duration oddly short. Check in Tag Assistant whether the same measurement ID loads twice, and remove one.
Comparing Analytics with other sources
It's normal to see differences when you compare GA4 with your hosting panel's statistics or with clicks in Search Console. Server statistics count bots too and don't depend on consent; Search Console counts only clicks from Google Search. What matters isn't a single number but the trend of the same source over time.
The real question is usually not 'how many visitors came' but 'how many called, filled in the form or wrote on WhatsApp'. We explain how to define those conversions as events in GA4 in our Google Analytics 4 setup guide. If you haven't set up Search Console either, start with Search Console setup; it shows search traffic regardless of consent.
If you'd like us to check your measurement setup from scratch and define conversion events, we do this as part of SEO consulting; for a quick check, write to us.
Frequently Asked Questions
How long does it take for data to appear in GA4?
The Realtime report updates within seconds; standard reports can lag by up to 24 to 48 hours. On a new property it's normal for standard reports to look empty on day one.
Why did my Analytics numbers drop after adding a cookie notice?
Visitors who don't consent are no longer measured with cookies. That's the natural result of complying with KVKK. You can still follow trends, and use Search Console for search traffic.
My site still has a code starting with UA-. Is that a problem?
Yes. Universal Analytics no longer collects data. Remove the code, create a GA4 property and add the new measurement ID starting with G-.
Blog posts are for general information only and are not a substitute for legal, financial or technical advice.
