6 Common Ads.txt Errors and How to Fix Them

Updated on: January 3, 2024
Uncover six common ads.txt errors that can impact your revenue and learn practical solutions to fix them. Secure your ad revenue with the correct ads.txt implementation.

Ad fraud continues to be a growing concern within the digital advertising industry. To address this issue, the Interactive Advertising Bureau (IAB) launched ads.txt in 2017, a solution increasingly adopted by publishers worldwide.

Ads.txt is an initiative designed to ensure that demand-side platforms and advertisers can verify authorized sellers and resellers of your ad inventories. This verification provides crucial protection against ad fraud, such as domain spoofing.

Despite the effectiveness of ads.txt, an article by eMarketer highlighted in 2018 points out that 16% of publishers among the top 5,000 websites were losing money at that time due to incorrect implementation of ads.txt files. 

The main issue lies in creating an Ads.txt file that follows a specific format. Any deviation from this format can invalidate the file, leading to lost potential revenue.

In this blog post, we aim to shed light on the importance of ads.txt and highlight common errors publishers often make during its implementation. 

We will also provide you with solutions to fix these errors to safeguard your revenue.

The Growing Importance of Ads.txt

The growing importance of ads.txt is evident from its widespread adoption by publishers across the globe. As more and more publishers recognize the value of ads.txt, it has become a crucial tool in the fight against ad fraud. This simple yet effective solution offers numerous benefits for publishers, advertisers, and demand-side partners alike.

For publishers, ads.txt helps maintain the integrity of their ad inventory, ensuring that only authorized sellers and resellers can sell their ad spaces. 

Advertisers and demand-side partners benefit from the increased transparency, as they can verify the authenticity of the ad inventory they’re buying. This ultimately leads to a safer and more trustworthy advertising ecosystem.

By understanding the importance of ads.txt and implementing it correctly, publishers can safeguard their revenue and protect their brand’s reputation.

How Ads.txt Errors Cause Publishers to Lose Money

Ads.txt errors are more common than you think, even among the top publishers. Mistakes in ads.txt files can significantly impact the protocol’s effectiveness, potentially leading to revenue loss and compromised programmatic advertising. Publishers must ensure the accuracy and proper implementation of their ads.txt files to avoid these pitfalls and maintain a transparent and secure advertising ecosystem. Major DSPs like Xandr and Google DV360 have been actively promoting the adoption of ads.txt while strictly adhering to the protocol themselves. 

They only deal with sellers and SSPs listed in your ads.txt files. This means that a typo or syntax error in your ads.txt files could cause them not to recognize and ignore your authorized sellers. 

Although an error in accurately listing a lesser-known demand partner might not result in a significant revenue loss, a similar mistake while listing a larger demand partner, such as Google, could cause publishers to lose substantial money.

Six Common Ads.txt Errors and Their Solutions

In this section, we’ll dive into some of the most common ads.txt errors publishers face and provide practical solutions to fix them. Don’t worry; we’ve got you covered!

1. Ads.txt file is not found

Problem: The most common error is that the ads.txt file cannot be found. This might be because you haven’t correctly created an ads.txt file or failed to add it to your domain.


  1. Set up Ads.txt file: Properly set up an ads.txt file and publish it on your domain. Refer to our detailed article on creating an Ads.txt file.
  2. Meet Impression Threshold: Ensure your Ad Exchange inventory has met or exceeded the 100 impression threshold within the last seven days for your domain to be visible in your ads.txt file.
  3. Be Patient with Changes: Remember that changes might be delayed if you have recently added a new developer website. It can take up to seven days for changes to reflect from the date of the addition.

2. Google Publisher ID is incorrectly formatted or missing

Problem: Your Google Publisher ID is a unique identifier associated with your Ad Exchange account. It’s a series of numbers with 16 digits and starts with the prefix ‘pub.’ 

This identifier lets advertisers and DSPs recognize you and lets them know about the inventory types enabled for your account. It should be included in your ads.txt file to allow advertisers, DSPs, and exchanges to crawl the file and recognize the legitimacy of sellers and resellers. 

However, it might be missing or formatted incorrectly, which can cause DSPs to become apprehensive about the details in the ads.txt file.


  1. Update Ads.txt file: Rectify an incorrectly formatted or missing publisher ID by updating your ads.txt file. Ensure the publisher ID is accurately written in your ads.txt file.
  2. Locate Publisher ID: Log into your Google Ad Manager account to find the publisher ID for your primary Ad Exchange and other linked accounts.
  3. Navigate to Settings: Click Admin > Global Settings > Ad Exchange account settings to access the publisher ID information.

3. Ads.txt has been uploaded, but AdSense is still asking to create one

Problem: Sometimes, you might have already uploaded your ads.txt file, but you still get a notification on your AdSense account asking you to create an ads.txt file.


  1. Wait for verification: Give AdSense time to auto-crawl and verify your ads.txt file. The process may take a few days to complete and update your ads.txt file status.
  2. Monitor ad requests: The process can take at least a month to update if you haven’t sent any ad requests from your website. Keep an eye on your ad requests during this time.

4. Ads.txt has not been uploaded to the root domain of your website

Problem: IAB specifically asks for ads.txt files to be uploaded to the root domain of your website. The ads.txt management tool in Ad Manager doesn’t accommodate showing a list of crawled subdomains. Addressing the situation is crucial if you have uploaded your ads.txt file to a subdomain.


  1. Identify the root domain: Make sure you know the root domain of your website, which should be a level down from the public suffix list (e.g., “google.co.uk” is acceptable, while “maps.google.co.uk” is not).
  2. Upload Ads.txt to root domains: If you have multiple root domains, ensure that an Ads.txt file is uploaded to each of them individually.
  3. Check Ads.txt Management: Click on Admin > Ads.txt Management in your Ad Manager account, and verify if the ads.txt file is successfully uploaded to each root domain.
  4. Contact CMS provider: If your CMS isn’t allowing you to upload a file to your root domain, contact your CMS provider immediately and ask them to support hosting your ads.txt file.

5. Ads.txt file contains syntax errors

Problem: A syntax error is a common issue with ads.txt files. IAB specifies that every ads.txt file needs to be properly formatted and written using a pre-ordained style. An error in doing so can invalidate your file or cause DSPs and advertisers to recognize your authorized sellers.


  1. Understand Formatting: Familiarize yourself with the proper formatting for an ads.txt file. Every line within an ads.txt spec file consists of 3-4 fields, with the first three mandatory and the fourth optional. Fields are separated using the comma “,”.
  2. Examine Your Ads.txt File: Review your ads.txt file and ensure that each line follows the proper format, such as

< SSP/Exchange Domain >, < SellerAccountID >, < PaymentsType >, < TAGID >

  1. Correct Errors: Rectify any syntax errors in your ads.txt file and ensure all authorized sellers are correctly represented.

For additional help, go through this link to learn about each field and its purpose.

6. Ads.txt file has not been validated

Problem: After making any changes or ensuring that an ads.txt file works correctly, validating it is imperative. An unvalidated Ads.txt file will not work, and it might not be possible for ad exchanges, SSPs, DSPs, or advertisers to crawl these files, making them ineffective.


  1. Access Ads.txt Management: In your Google Ad Manager account, click on Admin > Ads.txt Management. Ads.txt files for the web are displayed by default.
  2. View or Fix: In the column that says Action, click on either View or Fix in the correct row to edit the file settings. The opened file is the most recent version that Google has crawled.
  3. Check for Updates: If changes have been made to the ads.txt file since the last time Google crawled your website’s domain, the file you see is outdated and needs to be updated.
  4. Review Syntax: On the updated file, check each line in the dialogue window for syntax accuracy. Errors and warnings will be shown for each file. Hover over these to read the description and understand what kind of error or warning it is.
  5. Resolve Errors: Please refer to Google’s support article to resolve errors and warnings.
  6. Upload Updated File: Once the errors have been resolved, copy and paste the updated text into your ads.txt file and upload it to your website’s root domain.
  7. Check Crawling: Wait for 48 hours and check whether the updated ads.txt file is being crawled. To learn more about ensuring the crawling of your ads.txt file, refer to Google’s support article.

Best Practices for Managing Ads.txt

Managing ads.txt files can be daunting, especially if you’re unfamiliar with the technicalities involved. However, following some best practices can make this task much more manageable and ensure your ads.txt file is accurate and up-to-date. 

1. Regularly review ads.txt files

Reviewing your ads.txt files frequently is crucial to spot any discrepancies early and rectify them. Updating and checking your ads.txt files every week is the most recommended practice. This will enable you to quickly catch any errors, rectify them, and protect yourself from failed bid attempts.

2. List companies carefully in ads.txt files

Listing just any company or many companies can be hard to manage and cause fraudulent players to creep into your ads.txt files. Hence, you should carefully consider the companies you are choosing to list. Even a publisher as big as The New York Times has only 17 companies listed in their ads.txt file.

3. Invest in granular reporting tools

While it might be harder for smaller publishers to allocate the resources that larger publishers can easily manage, it is worth investing in reporting tools that give you a granular metrics view of ads.txt. This will increase your knowledge about ads.txt and provide information about the revenue impact of partners you have included in your ads.txt files.

6. Automate ads.txt file management

Automation is the key to a future relying heavily on ads.txt. Many tools in the open market can check for errors in your ads.txt files, and as the popularity of this IAB initiative gains traction with demand partners, such tools are only going to become better. Therefore, investing in such a tool is a wise choice for you.

Ads.txt: A Key Solution in Combating Ad Fraud

Ads.txt is poised to play a vital role in combating ad fraud as the industry progresses. With the continuous development and adoption of innovative technologies, ads.txt’s effectiveness will be further enhanced. 

Proper implementation of ads.txt is crucial, as it improves transparency, reduces ad fraud, and enhances the legitimacy of programmatic transactions. By embracing Ads.txt, publishers can contribute to a more secure and trustworthy digital advertising ecosystem.

Ultimately, the success of ads.txt will depend on the continued support and adoption of the initiative by publishers, advertisers, and other players in the industry.

We hope that this article has helped provide you with a better understanding of ads.txt and its importance in ad fraud prevention. If you have any questions or comments, please feel free to contact us. We are always happy to help.

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