He DAV system address book sync has not run yet as your instance has more than 1000 users or because an error occurred. Please run it manually by calling "occ dav:sync-system-addressbook"

ℹ️ Support
1

I have a problem with the path: “occ dav:sync-system-addressbook”.

In which file I should run this command ??

2

Please see the Admin Manual chapter covering this topic: Using the occ command — Nextcloud latest Administration Manual latest documentation