The tag is installed incorrectly. For example, the CMS modified the tag code. Reinstall the tag or contact the support service for your CMS.
Broken scripts are preventing the Yandex Metrica tag from working on the site. You can check this in the browser console.
The recommendations did not help
This means that information is being transmitted to Yandex Metrica. However, the data might not be shown in reports for any of the following reasons:
Data is sent to a tag with a different number.
The Filters tab in the tag settings has overly strict filters defined. Remove unneeded filters.
The Filters tab in the tag settings has the Don’t count my sessions filter enabled. This means that the tag doesn't register your own sessions. Try accessing the site with your browser in “incognito” mode.