Fix ERR HTTP2 Inadequate Transport Security error in Google Chrome

This post talks about how to fix ERR HTTP2 Inadequate Transport Security error in Google Chrome. A lot of users have encountered this error message while connecting to a CA server over HTTPS in the Google Chrome browser. It occurs due to some security settings.

Before we talk about the solutions, let us find out the reasons and scenarios that may trigger this error in Chrome.

What causes ERR_HTTP2_Inadequate_Transport_Security Error in Google Chrome?

Here are some of the potential causes for the ERR_HTTP2_Inadequate_Transport_Security error to trigger in Chrome:

This error might be a result of using an outdated version of Chrome. With the older version of Chrome, your browser must be missing out on various new security mechanisms essential for establishing CA connections, and thus this error message. If this scenario applies to you, a simple update to the latest version of Chrome will fix the issue.
Certain old and corrupted browser cookies can also cause this error message in Chrome. In that case, you can simply clear all the cookies for that particular connection that threw this error message.
Another reason for the same can be the fact that HTTP/2 is enabled. It is good for security but has stricter requirements. Windows Server 2016 tends to fall back to HTTP/1.1 that might cause this error message.
If your Windows Server is using weaker ciphers and protocols, this error message might be triggered due to that.

Now that you know the scenarios triggering this error message in Chrome, let us discuss the fixes to resolve the issue.

ERR_HTTP2_Inadequate_Transport_Security error in Chrome

Here are the main methods you can try to fix ERR_HTTP2_Inadequate_Transport_Security Error in Google Chrome:

Delete Chrome Cookies.
Update Chrome to the latest version.
Turn Off HTTP/2 on Windows Server.
Disable Weak Cipher suites.

Let us talk about the above solutions in detail now.

1] Delete Chrome Cookies

As we discussed above, stored cookies on your Chrome browser can be a reason for the ERR_HTTP2_Inadequate_Transport_Security error. This error message is common when connecting to a CA server via HTTPS on Windows Server installation. Now, you can check if this error is caused due to bad cookies by establishing the same connection in an incognito tab.

For doing that, launch Google Chrome and click on the three-dot menu icon present at the top-right corner. Then, click on the New incognito window option to launch the incognito tab. Now, try making a connection to the same portal that gave you this error and see if the error message still shows up. If you don’t get this error in incognito mode, you can be sure that the issue is triggered due to bad or corrupted browser cookies, and you will need to delete cookies from Chrome. However, in case the error still shows up in incognito mode, you can skip this method.

To fix the ERR_HTTP2_Inadequate_Transport_Security error, you can try deleting the dedicated bad cookie using the below steps:

First, launch the Google Chrome browser and try loading up the page that triggered this error from the address bar.
Now, from the address bar, click on the lock icon present beside the connection URL.
Next, you will see various menu options from which you need to tap on the Cookies option.
After that, go to the Allowed tab inside the Cookies menu.
Then, select each of the cookies and click on the Remove button to delete all bad cookies one by one.
Once you finish deleting all possibly corrupt and bad cookies, close Chrome and then relaunch it.

Now, check if this error is fixed or not. If not, try some other fix from this list.

See: Fix Chrome won’t open or launch on Windows 11/10 PC

2] Update Chrome to the latest version

You also need to make sure that you are using the latest public version of Google Chrome to avoid this error. If you are using an older version of Chrome that is missing the new security mechanisms, you might receive this error. Some users have reportedly fixed this issue by updating their Chrome to the most recent update. You can go to the three-dot menu and click on the Help > About Google Chrome option. Then, check for the updates available, install the latest updates, and restart your web browser.

However, it is recommended to uninstall the Chrome browser completely using a free uninstaller that can delete remnant and leftover files as well. After Chrome installation, download the latest version of Chrome from its official website and then run the installer to install the browser on your PC. Once the Chrome installation is completed, check if the error ERR_HTTP2_Inadequate_Transport_Security still persists on connecting to the portal that was giving you this error.

3] Turn Off HTTP/2 on Windows Server

Are you receiving this error after upgrading from the IIS webserver to Windows Server? Then, the error might be caused since by default Windows Server turns on HTTP/2 and might fall back to HTTP/1.1 in case HTTP/2 is not supported. So, you can try disabling HTTP/2 on Windows Server to fix the issue. However, it might be a compromise on security. So, do that only if it is too required.

If you are sure of disabling HTTP/2 on Windows Server and make this compromise, you can do that by manually creating a registry file. here are the steps to do that:

Firstly, open the Notepad application on your PC with admin privilege; search notepad in the search box and then right-click on the Notepad application and select the Run as administrator option.

Now, in the Notepad, type the below code:

Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\HTTP\Parameters]
“EnableHttp2Tls”=dword:00000000
“EnableHttp2Cleartext”=dword:00000000

After writing the code, go to the File menu and click on the Save as option.

Next, select the Save as type to All Files, enter a filename with the .reg file extension, and click on the save button to save the registry file.

Now, right-click on the created registry file and then from the context menu, click on the Run as administrator option and confirm to run the registry script.

Finally, restart Windows Server installation to save changes and go back to Google Chrome and see if you still get the error.

Note: If you decide to enable HTTP/2 in the future, you can create a new registry file using the above steps but just make sure to use the below script:

Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\HTTP\Parameters]
“EnableHttp2Tls”=dword:1
“EnableHttp2Cleartext”=dword:1

Read: Fix ERR_FILE_NOT_FOUND error on Google Chrome

4] Disable Weak Cipher suite using IIS Crypto

You can also try disabling weaker cipher suites in order to fix this error in Chrome. To do that without any hassle or noise, you can use this free tool called IIS Crypto. It is free software that lets you enable or disable ciphers, protocols, hashes, and key exchange algorithms on Windows Server 2008, 2012, 2016, and 2019 with a single click.

You can download this software on your PC and then launch this application. It is portable, so requires no installation. After starting this software, click on the Cipher Suites menu present on the left panel and then press on the Best Practices button. Doing this will disable weaker cipher suites and protocols and make your server use the best practices for TLS. The advanced users can manually select/ deselect weaker cipher suites accordingly. To save changes, click on the Apply button and reboot your PC. This will disable all the weaker ciphers and make sure you are using secure protocols on your Windows Server.

See if this method works for you and enables you to get rid of the error in Chrome.

How do I fix Chrome installation error?

If you are receiving a Chrome installation error, You can try some common fixes to fix it up. Check your internet connection and make sure you are connected to a stable connection. If there are lagging or connectivity issues with your connection, you might encounter a Chrome installation error. Also, make sure your device meets the system requirements. You can also download a new installation file for Chrome and then attempt to install the browser using the new file. If that doesn’t help, you can use an offline installer to install it.

If you are receiving a particular error code on Chrome installation, here are some guides that will help you fix them up:

How do I Fix Chrome out of memory error?

If you are encountering a Google Chrome ran out of memory error message, you can fix it up by clearing up the cache, closing all instances of Chrome and restarting the browser, or removing extensions. If that doesn’t help, you can try creating a new user profile and check if the issue is fixed.

That’s it!

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