Title: Fatal error: Uncaught Error: Call to undefined function wp_theme_has_theme_json(
Last modified: April 3, 2023

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# Fatal error: Uncaught Error: Call to undefined function wp_theme_has_theme_json(

 *  [kubanondrej](https://wordpress.org/support/users/kubanondrej/)
 * (@kubanondrej)
 * [3 years, 2 months ago](https://wordpress.org/support/topic/fatal-error-uncaught-error-call-to-undefined-function-wp_theme_has_theme_json/)
 * Hi guys,
 * when I go in wp-admin into Pages and try to edit existing page (by click on page
   name or Edit) then I will get this error mentioned below. Do you know how to 
   solve it, please?
 *     ```wp-block-code
       Fatal error: Uncaught Error: Call to undefined function wp_theme_has_theme_json() in /home/users/galanterieroznov/masaze-roznov.jednoduse.cz/web/wp-admin/edit-form-blocks.php:206 Stack trace: #0 /home/users/galanterieroznov/masaze-roznov.jednoduse.cz/web/wp-admin/post.php(187): require() #1 {main} thrown in /home/users/galanterieroznov/masaze-roznov.jednoduse.cz/web/wp-admin/edit-form-blocks.php on line 206http://masaze-roznov.jednoduse.cz/
       ```
   

Viewing 2 replies - 1 through 2 (of 2 total)

 *  Moderator [James Huff](https://wordpress.org/support/users/macmanx/)
 * (@macmanx)
 * [3 years, 2 months ago](https://wordpress.org/support/topic/fatal-error-uncaught-error-call-to-undefined-function-wp_theme_has_theme_json/#post-16617391)
 * This problem may be a plugin or theme conflict. Please attempt to deactivate 
   all plugins and switch to the default Twenty Twenty-One theme. If the problem
   goes away, re-activate them one by one to identify the source of the problem.
 * If you can install plugins, install [Health Check](https://wordpress.org/plugins/health-check/).
   On the troubleshooting tab, you can click the button to deactivate all plugins
   and change the theme for you while you’re still logged in **without affecting
   normal visitors to your site**.
 *  [Shameem Reza](https://wordpress.org/support/users/codechef/)
 * (@codechef)
 * [3 years, 2 months ago](https://wordpress.org/support/topic/fatal-error-uncaught-error-call-to-undefined-function-wp_theme_has_theme_json/#post-16618956)
 * Hello [@kubanondrej](https://wordpress.org/support/users/kubanondrej/)
 * This error message is usually caused by an outdated WordPress version or theme,
   or a conflict with a plugin. Here are some troubleshooting steps that you can
   follow to fix the issue:
    1. **Update WordPress and Themes:** Ensure you are using the latest version of 
       WordPress and your themes. You can check for updates by navigating to Dashboard
       > Updates. If updates are available, update them and see if the issue goes away.
    2. **Disable Plugins:** Sometimes, the issue can be caused by a plugin that conflicts
       with your theme. You can try disabling all your plugins and see if the issue
       goes away. If it does, you can start reactivating your plugins individually 
       to find the one causing the issue.
    3. **Check for Compatibility:** Make sure your theme is compatible with the version
       of WordPress that you are using. You can check the theme’s documentation or 
       contact the theme’s developer to confirm compatibility.
    4. **Switch to a Default Theme: **You can try switching to a default WordPress 
       theme (like Twenty Twenty-Three) to see if the issue goes away. If it does, 
       then the issue is likely with your current theme.

Viewing 2 replies - 1 through 2 (of 2 total)

The topic ‘Fatal error: Uncaught Error: Call to undefined function wp_theme_has_theme_json(’
is closed to new replies.

## Tags

 * [undefined function](https://wordpress.org/support/topic-tag/undefined-function/)

 * In: [Fixing WordPress](https://wordpress.org/support/forum/how-to-and-troubleshooting/)
 * 2 replies
 * 3 participants
 * Last reply from: [Shameem Reza](https://wordpress.org/support/users/codechef/)
 * Last activity: [3 years, 2 months ago](https://wordpress.org/support/topic/fatal-error-uncaught-error-call-to-undefined-function-wp_theme_has_theme_json/#post-16618956)
 * Status: not resolved

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