Google Analytics: 404 reports in GA4

If 404 errors are among the top pages accessed on a site, you can pull a report which shows each of the URLs which are generating those errors. By doing this, you may be able to correct the errors by creating redirects to more appropriate URLs. You'll need to log in to Google Analytics and locate the GA4 property in your account. Then you can follow these steps:

Go to Reports:

Choose Engagement > Pages and Screens

1. In the search box under the graph, add 404 and hit Enter on your keyboard (important step!)
2. Then set the dropdown to Page title and screen class - this is referred to as the 'primary dimension'.

Click the + (plus) to the right...

...and choose Page/Screen > Page path and screen class - this is referred to as the 'secondary dimension'

1. Now you can see the page names associated with each 404 error
2. You can adjust the number of visible rows on the screen
3. You can adjust the date range of the report
4. You can download the report as a PDF or CSV

By pulling this report, you can create redirects on the site for each of the listed pages so that visitors will no longer see 404 errors when clicking links from search engines ... and - over time - 404 errors should disappear from among the most accessed pages.