Ads.txt helps ensure your ad space is only sold through sellers (e.g., AdSense) who you've identified as authorized. Advertisers who use some of our ads products to buy ad space on publisher sites now have the option to only bid on inventory from sellers that are classified as authorized through ads.txt.
To ensure that prospective advertisers can continue to bid on your ad space, it’s important to create and publish an ads.txt file on all your sites.
Before you start
There are a couple YouTube videos on ads.txt that you might find useful:
Identify the issue
If you're having issues with your ads.txt file, follow the steps below and select the answers that best describe your situation.