GA4 shows zero users today but had data yesterday

Yesterday was normal, today is flat zero. Before you panic, rule out GA4's normal reporting lag. If Realtime is also empty, though, your tag genuinely stopped firing, and that almost always points to a recent change.

First, rule out lag

GA4's standard reports can lag 24 to 48 hours, so today often looks low simply because it is not processed yet. The real test is Realtime: open it and load your own site. If you appear, data is flowing and today's emptiness is just processing lag. If Realtime is also empty, the tag is down.

What stops a tag overnight

• A deploy or publish: a code change or a GTM publish that broke tracking went out late yesterday.
• The GTM container stopped loading entirely.
• Consent or CSP change now blocking the tag.
• Billing or property issue, rarer, but worth a glance.

How to get it back

Check what shipped around the time data stopped, then confirm the tag in DebugView and GTM Preview. Reinstate the snippet or roll back the breaking change, verify Realtime fills, and you are back. A sudden flatline dated to a deploy is the fastest kind of tracking break to fix, because the cause is usually the last thing you changed.

Datahound are analytics and ad-tracking specialists. We fix broken GA4, Google Tag Manager and server-side tracking so every sale, form and call gets counted. Back to datahound.agency · All tracking guides · Realtime works but reports are empty