How to Fix AdSense TCF Errors in 2026: Complete Guide

Fix AdSense TCF errors can reduce advertising coverage, cause requests to use limited or non-personalized ads, or prevent an advertisement from being served. These errors generally occur when the consent information sent by your Consent Management Platform is missing, malformed, outdated or incompatible with Google’s requirements.

TCF stands for the Transparency and Consent Framework developed by IAB Europe. A registered CMP presents privacy choices to visitors, creates a Transparency and Consent string—commonly called a TC string—and makes that information available to advertising vendors.

When your website uses a registered TCF CMP, AdSense can automatically consume the TC string. Problems occur when the CMP does not respond correctly, sends an invalid string, omits Google from its vendor configuration or fails to send TCF signals with an eligible advertising request. 3

This guide explains how to download the TCF report, understand the primary error codes and complete a practical AdSense TCF errors troubleshooting process.

What Is the AdSense TCF Error Report?

The TCF error report contains consent-related errors detected on your websites during the previous seven days.

Google says the report can contain:

• Domain or mobile application ID
• Associated ad-unit path
• TCF error code
• Number of affected queries
• Last date the error was detected

The report is available only when Google has detected relevant errors during the previous seven days. 4

How to Download the AdSense TCF Error Report

Google’s current Help instructions provide this route:

1. Sign in to Google AdSense.
2. Open Brand safety.
3. Select Content.
4. Open Blocking controls.
5. Click Manage European regulations.
6. Locate the TCF notification.
7. Click Download TCF error report.
8. Open the downloaded file in Google Sheets or Microsoft Excel.

AdSense interface labels can occasionally vary between accounts, so also review Privacy & messaging and the European regulations section if the report is not visible through the first route. The download option appears only when errors have been detected recently. 4

Important TCF v2.3 Change in 2026

TCF v2.3 became mandatory for TC strings generated on or after March 1, 2026. Google continues accepting older TCF v2.1 and v2.2 strings that were generated before February 28, 2026, subject to the applicable framework policy. 3

TCF v2.3 makes the Disclosed Vendors segment mandatory. This segment records which vendors were disclosed to the visitor by the CMP. 5

Google introduced error code 1.4 when:

• The Disclosed Vendors segment is missing
• The segment is malformed
• Google is not included
• Google cannot process the segment

A website using a third-party CMP should confirm that the provider supports TCF v2.3 and includes Google Advertising Products, vendor ID 755, in its configuration. 6

AdSense TCF Error Codes and Solutions

Google attempts different serving behaviours depending on the issue. Some errors can result in limited ads, error 9.1 can lead Google to attempt non-personalized ads, and invalid TC strings may prevent an ad from being served. 4

How to Fix AdSense TCF Errors Step by Step

1. Confirm That Your CMP Is Google-Certified

Error 9.1 means Google detected a TCF CMP, but that CMP was not certified by Google.

Check that:

• Your CMP appears on Google’s current certified-CMP list.
• Certification applies to websites, not only mobile applications.
• The correct CMP version is installed.
• Your plan or account includes TCF support.
• An old CMP script is not still running.
• A WordPress plugin is not loading a second cookie banner.

Google attempts to serve non-personalized ads when error 9.1 occurs, but advertising performance may be affected. 7

If your provider is not certified, either ask it to complete Google certification or migrate to Google’s CMP or another certified provider.

2. Confirm That the CMP Supports TCF v2.3

Open your CMP dashboard and look for:

• TCF v2.3 support
• Current CMP script version
• Current Global Vendor List
• Disclosed Vendors support
• Service-specific TC strings
• Google vendor configuration

If the CMP generates new TCF v2.2 strings after March 1, 2026, affected requests may default to limited ads or be dropped. Google’s CMP was updated to produce TCF v2.3 strings by the deadline. 3

Do not rely on an old WordPress tutorial or an outdated plugin that has not been updated for TCF v2.3.

3. Fix TCF Error 1.4

Error 1.4 is one of the most important new AdSense TCF errors in 2026.

To fix it:

1. Confirm that your CMP supports TCF v2.3.
2. Open its vendor configuration.
3. Search for Google Advertising Products.
4. Confirm that vendor ID 755 is selected.
5. Enable the required Disclosed Vendors segment.
6. Update the CMP script if necessary.
7. Republish the consent message.
8. Request fresh consent from affected visitors.
9. Clear only relevant consent-testing data when performing your own tests.
10. Monitor the next TCF error report.

The TCF v2.3 Disclosed Vendors segment must be present and correctly formatted, and Google must be included for Google to operate on the request. 6

4. Fix CMP Timing Errors 2.1a and 2.1b

Error 2.1a can occur when the advertising tag requests consent data while the CMP remains in one of these states:

stub
loading
error

The CMP should respond immediately to addEventListener, even while its interface is loading. If the CMP does not respond correctly, the advertising request may remain unmonetized. 8

If you manually control when advertisements load, wait until the TC data indicates an appropriate state, such as:

tcloaded

or, after the visitor makes a choice:

useractioncomplete

Do not load personalized advertising merely because the consent message is visible. Wait for the CMP to return usable consent data.

Error 2.1b appears when the request contains:

gdpr=1

and a consent parameter is present, but the actual TC string is empty. Ask your CMP or developer to correct how the string is passed to the advertising request. 4

5. Test the TCF API in Your Browser

You can use the browser Console to confirm whether the CMP API is available.

Open an eligible page and follow these steps:

1. Right-click the page.
2. Select Inspect.
3. Open Console.
4. Enter:

window.__tcfapi?.('ping', 2, function (data, success) {
  console.log('TCF ping success:', success);
  console.log('TCF ping data:', data);
});

You can also inspect TC data using:

window.__tcfapi?.('addEventListener', 2, function (tcData, success) {
  console.log({
    success: success,
    cmpStatus: tcData?.cmpStatus,
    eventStatus: tcData?.eventStatus,
    gdprApplies: tcData?.gdprApplies,
    tcStringPresent: Boolean(tcData?.tcString),
    googleVendorConsent: tcData?.vendor?.consents?.[755],
    googleVendorLegitimateInterest:
      tcData?.vendor?.legitimateInterests?.[755],
    disclosedVendors: tcData?.disclosedVendors
  });
});

The TCF API uses the general format:

__tcfapi(command, version, callback, parameter)

The ping, addEventListener and removeEventListener functions are part of the CMP API specification. 9

This test is a technical diagnostic only. It does not determine whether your website is legally compliant.

6. Fix Invalid CMP ID Error 3.1

Each registered TCF CMP receives a CMP ID. Error 3.1 indicates that the TC string contains an invalid ID.

This can happen when:

• A developer used a testing CMP ID on the live site.
• The CMP ID was entered manually and incorrectly.
• A former CMP provider’s cookie remains stored.
• The CMP is no longer listed as valid.
• An outdated script generates old TC strings.

Check the installed script against the current code supplied by your CMP. After correcting the implementation, request consent again so that affected visitors receive a fresh string containing the valid CMP ID. 10

7. Re-Obtain Consent When Necessary

Correcting the CMP code does not automatically update every TC string already stored in visitors’ browsers.

Google recommends considering re-consent for errors involving:

• Google missing as a vendor
• Invalid CMP IDs
• An outdated GVL
• Out-of-band consent
• Globally scoped consent
• An outdated TCF version

Your CMP should provide a supported method for invalidating old strings or requesting privacy choices again. 4

Do not repeatedly show a consent message to every visitor without a valid technical, policy or legal reason. Configure re-consent according to your CMP’s documentation and applicable requirements.

8. Fix Additional Consent Errors 8.1 and 8.2

The Additional Consent string is used for Google advertising technology providers that are not registered on the IAB Global Vendor List.

Error 8.1 means the AC string does not use the required version separator:

~

Error 8.2 means the vendor-ID list does not use the expected dot-separated format.

A simplified AC v2 structure can resemble:

2~1.35.41~dv.9.21.81

The current version begins with 2, uses ~ separators and represents vendor IDs as dot-separated numbers. Only a registered CMP should create the Additional Consent string. 11

Do not manually generate or edit production AC strings inside WordPress or a theme file. Ask your CMP provider to correct the implementation.

9. Fix TCF Error 10.1

Error 10.1 means an ad request from the EEA, UK or Switzerland—or a request manually marked with gdpr=1—did not contain TCF signals.

Check whether:

• The CMP code loads on every article.
• The header script appears before advertising requests.
• Cache optimization removes the CMP from some pages.
• The website uses a certified TCF CMP.
• AdSense code fires before consent data is available.
• gdpr=1 is incorrectly forced for all global visitors.
• A custom ad script omits the consent parameter.
• Some WordPress templates do not load the consent plugin.

Google attempts to serve limited ads when error 10.1 occurs. 7

WordPress TCF Troubleshooting Checklist

If your website uses WordPress, check the following:

1. Use only one primary CMP.
2. Remove inactive cookie-banner plugins.
3. Check the live page source for duplicate CMP scripts.
4. Do not delay the CMP script behind optional JavaScript optimization.
5. Make sure the CMP appears on posts, pages and categories.
6. Test logged-out pages.
7. Clear WordPress and CDN caches after updating the CMP.
8. Check whether geo-caching serves the wrong consent version.
9. Confirm that AdSense does not load before consent is ready.
10. Test mobile and desktop browsers.
11. Republish the European regulations message after changing vendors.
12. Check that Google vendor ID 755 is configured.
13. Confirm that your CMP supports TCF v2.3.
14. Download a new error report after allowing time for fresh traffic.

Be careful with optimization plugins that delay all third-party JavaScript. A delayed CMP response can cause advertising requests to proceed without usable TCF data. Google recommends that the CMP respond immediately to addEventListener. 8

How Long Does It Take for TCF Errors to Disappear?

Google’s TCF error report covers errors detected during the previous seven days. Therefore, even after fixing the CMP, older detections may remain temporarily visible until they fall outside the reporting window.

This is an inference based on the report’s seven-day coverage rather than a guaranteed correction timeline. Continue monitoring the error count and the “last detected” date. A successful fix should generally result in fewer new detections rather than an immediate empty report. 4

Do not keep modifying a correct implementation every few hours. Allow enough valid traffic to generate a meaningful new report.

How to Measure the Revenue Impact

AdSense’s Serving restriction reporting breakdown can show categories including:

• Limited ads
• Restricted data processing
• Non-personalized ads
• Basic ads
• Personalization disabled
• No restriction

This report can help you understand how consent and personalization restrictions affect traffic and revenue. Policy-related serving restrictions are not included in this breakdown and should be reviewed separately in the Policy Center. 12

Compare:

• Page views
• Coverage
• Ad impressions
• Page RPM
• Limited-ad traffic
• Non-personalized-ad traffic
• EEA, UK and Swiss revenue
• TCF error count
• Last detected error date

Do not judge a CMP only by consent rate. It must correctly represent visitor choices and send accurate signals.

Common Mistakes to Avoid

Do not:

• Ignore high-volume TCF errors.
• Assume every error represents a visitor rejecting consent.
• Use a non-certified CMP.
• Generate new TCF v2.2 strings after March 1, 2026.
• Remove Google from the vendor configuration accidentally.
• Load AdSense before the CMP is ready.
• Run two consent plugins simultaneously.
• Force gdpr=1 on every request without understanding the implementation.
• Manually construct TC or AC strings.
• Edit only the homepage while other templates remain broken.
• Test only while logged into WordPress.
• Request consent repeatedly without a valid reason.
• Treat technical CMP certification as full legal compliance.

AdSense TCF Errors Final Checklist

•  My CMP is registered with IAB Europe.
•  My CMP is certified by Google.
•  My CMP supports TCF v2.3.
•  Google Advertising Products vendor ID 755 is included.
•  The Disclosed Vendors segment is present.
•  The CMP API loads on every eligible page.
•  addEventListener responds correctly.
•  Ad requests wait for usable consent data.
•  No request contains an empty TC string.
•  The CMP ID is valid.
•  The latest Global Vendor List is used.
•  TC strings are service-specific.
•  No out-of-band signals are used.
•  Additional Consent strings are correctly formatted.
•  Only one CMP controls the consent process.
•  WordPress caching does not remove the CMP.
•  Old invalid strings have been addressed.
•  The TCF report is monitored regularly.
•  Serving restrictions are reviewed in AdSense reports.
•  A privacy professional has reviewed the legal configuration where necessary.

Frequently Asked Questions

What are AdSense TCF errors?

They are errors Google detects in the consent information connected to advertising requests. They can involve missing, malformed, outdated or incorrectly configured TC strings.

What is TCF error 1.4?

Error 1.4 means the mandatory TCF v2.3 Disclosed Vendors segment is missing, malformed or does not include Google. Confirm that Google Advertising Products, vendor ID 755, is included in your CMP configuration. 6

Is TCF v2.3 mandatory for AdSense?

TCF v2.3 is mandatory for new TC strings generated on or after March 1, 2026. Google continues accepting qualifying older TCF v2.1 and v2.2 strings generated before February 28, 2026. 3

What is Google’s TCF vendor ID?

Google Advertising Products uses vendor ID 755 in the IAB Global Vendor List. 6

Why is error 9.1 appearing?

Error 9.1 appears when a TCF CMP is present but is not certified by Google. Migrate to a certified CMP or ask the current provider about certification. 7

What causes error 10.1?

It occurs when a request from an eligible region—or one marked with gdpr=1—does not contain TCF signals. Check that the CMP loads before advertisements and is installed across every relevant template. 4

Can TCF errors reduce AdSense revenue?

Yes. Depending on the error, Google may attempt to serve limited or non-personalized ads, or the request may remain unmonetized. The actual impact depends on traffic, advertiser demand and the number of affected requests. 3

Should I manually edit the TC string?

No. TC strings should be created and managed by an IAB-registered CMP. Correct the CMP configuration instead of manually changing stored strings. 5

Does Google CMP support TCF v2.3?

Yes. Google’s consent-management solution supports TCF v2.3 for European regulations messages. 4

How often should I download the report?

Check it after CMP changes and periodically when your website receives EEA, UK or Swiss traffic. The report is available only when relevant errors were detected during the previous seven days. 4

Conclusion

The correct way to fix AdSense TCF errors is to identify the highest-volume error codes, verify your CMP’s certification and make sure the implementation supports TCF v2.3.

Pay particular attention to error 1.4, Google vendor ID 755, CMP API timing and missing TCF signals. Errors 9.1 and 10.1 generally indicate certification or coverage problems, while errors 2.1a and 2.1b usually require technical work on CMP timing and string delivery.

After making corrections, request fresh consent when appropriate, clear relevant website caches and monitor the report’s error count and last-detected date. Do not attempt to solve consent problems by manually creating TC strings or hiding the consent interface.

A correctly configured CMP can improve advertising eligibility and reduce lost requests, but publishers remain responsible for both Google policy compliance and applicable legal requirements.