In order to pass this test, the ads.txt file should be publicly available in the website's root domain and its content should be properly formatted.
The advertising systems will read the content of the ads.txt file only if the request will return a 200 OK HTTP status code. The content of this file should be encoded as a formatted plain text and the HTTP Content-Type header should be text/plain (all other Content-Types are treated as an error and the content will be ignored).
As outlined in the IAB Tech Lab specifications for ads.txt file, the format logically consists of three types of records: comments, data records and variables:
<FIELD #1>, <FIELD #2>, <FIELD #3>, <FIELD #4>
Any line containing a pattern of <VARIABLE>=<VALUE> should be interpreted as a variable declaration. The <VARIABLE> is a string identifier without internal whitespace. The only supported separator is the equals sign ‘=’. The <VALUE> is an open string that may contain arbitrary data.
For human readability it is recommended that variables be declared at the end of the file, but this is not a strict requirement.
Only the following variables are supported: CONTACT, SUBDOMAIN and INVENTORYPARTNERDOMAIN.