what the fuck
2017 some money invented a new “standard” for websites … and when you dont obey your logfiles will be plasterd with 404’s …
so what to do?
first put
#about the ads.txt
User-agent: *
Disallow: /ads.txt
in your robots.txt … see more
second put a new *.txt file in your root directory wich contains
placeholder.example.com, placeholder, DIRECT, placeholder
source: https://en.wikipedia.org/wiki/Ads.txt