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Ads.txt Implementation Errors

These are the most common errors publishers make in their ads.txt files. Buyers use crawlers that block domains because of these errors, resulting in revenue loss for publishers. Download the lists and check if your domain is included.
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This is the most common error we see publishers make and the easiest to fix. To be certain that crawlers can crawl your domain, the domain URL should be encrypted as HTTPS rather than HTTP.
2 Sub vs. Top-domain
Make sure to keep your ads.txt file on the top domain rather than the 'www' subdomain. By default, crawlers use top-domain, and won't fetch subdomain ads.txt unless redirected.
3 Not Plain text
Ensure that your ads.txt file appears on a plain text file and not HTML documents. Additionally, the header must state: "Content-Type: text/plain."
content-type: text/html; charset=UTF-8
content-type: text/plain; charset=UTF-8
4 Blocked non-standard User-Agents
Blocked non-standard user-agents (UA) is the second most common error we see. Here, make sure that your ads.txt is available to any UA and is not getting blocked. This will ensure that any crawler can access it.
user-agent: Sellers.Guide Crawler
User-Agent: Mozilla/5.0 <platform> <extensions>