Title: Fatal error: Uncaught Error: Undefined constant “HEADER”
Last modified: May 4, 2021

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# Fatal error: Uncaught Error: Undefined constant “HEADER”

 *  [dianne92](https://wordpress.org/support/users/dianne92/)
 * (@dianne92)
 * [5 years, 1 month ago](https://wordpress.org/support/topic/fatal-error-uncaught-error-undefined-constant-header/)
 * After updating to wordpress 5.7.1 I got this error and cannot activate this theme
   anymore.
 * `Fatal error: Uncaught Error: Undefined constant "HEADER" in /var/www/hempoilcbdbenefits.
   com/html/wp-content/themes/sparkling/inc/custom-header.php:56 Stack trace: #0/
   var/www/hempoilcbdbenefits.com/html/wp-includes/class-wp-hook.php(292): sparkling_header_style()#
   1 /var/www/hempoilcbdbenefits.com/html/wp-includes/class-wp-hook.php(316): WP_Hook-
   >apply_filters() #2 /var/www/hempoilcbdbenefits.com/html/wp-includes/plugin.php(
   484): WP_Hook->do_action() #3 /var/www/hempoilcbdbenefits.com/html/wp-includes/
   general-template.php(3009): do_action() #4 /var/www/hempoilcbdbenefits.com/html/
   wp-content/themes/sparkling/header.php(30): wp_head() #5 /var/www/hempoilcbdbenefits.
   com/html/wp-includes/template.php(730): require_once('...') #6 /var/www/hempoilcbdbenefits.
   com/html/wp-includes/template.php(676): load_template() #7 /var/www/hempoilcbdbenefits.
   com/html/wp-includes/general-template.php(48): locate_template() #8 /var/www/
   hempoilcbdbenefits.com/html/wp-content/themes/sparkling/index.php(11): get_header()#
   9 /var/www/hempoilcbdbenefits.com/html/wp-includes/template-loader.php(106): 
   include('...') #10 /var/www/hempoilcbdbenefits.com/html/wp-blog-header.php(19):
   require_once('...') #11 /var/www/hempoilcbdbenefits.com/html/index.php(17): require('...')#
   12 {main} thrown in /var/www/hempoilcbdbenefits.com/html/wp-content/themes/sparkling/
   inc/custom-header.php on line 56`
 * This is my server configuration:
 *     ```
       Server architecture	Linux 4.18.0-240.22.1.el8_3.x86_64 x86_64
       Web server	Apache/2.4.37 (centos) OpenSSL/1.1.1g
       PHP version	8.0.5 (Supports 64bit values)
       PHP SAPI	fpm-fcgi
       PHP max input variables	1000
       PHP time limit	600
       PHP memory limit	1024M
       Max input time	600
       Upload max filesize	1024M
       PHP post max size	1024M
       cURL version	7.61.1 OpenSSL/1.1.1g
       Is SUHOSIN installed?	No
       Is the Imagick library available?	Yes
       Are pretty permalinks supported?	Yes
       .htaccess rules	Custom rules have been added to your .htaccess file.
       ```
   
 * The page I need help with: _[[log in](https://login.wordpress.org/?redirect_to=https%3A%2F%2Fwordpress.org%2Fsupport%2Ftopic%2Ffatal-error-uncaught-error-undefined-constant-header%2F%3Foutput_format%3Dmd&locale=en_US)
   to see the link]_

Viewing 1 replies (of 1 total)

 *  [ABCdatos](https://wordpress.org/support/users/abcdatos/)
 * (@abcdatos)
 * [5 years, 1 month ago](https://wordpress.org/support/topic/fatal-error-uncaught-error-undefined-constant-header/#post-14397956)
 * Try PHP 7.4.
 * [https://wordpress.org/support/topic/php-8-not-compatible/](https://wordpress.org/support/topic/php-8-not-compatible/)

Viewing 1 replies (of 1 total)

The topic ‘Fatal error: Uncaught Error: Undefined constant “HEADER”’ is closed to
new replies.

 * ![](https://i0.wp.com/themes.svn.wordpress.org/sparkling/2.4.11/screenshot.png)
 * Sparkling
 * [Support Threads](https://wordpress.org/support/theme/sparkling/)
 * [Active Topics](https://wordpress.org/support/theme/sparkling/active/)
 * [Unresolved Topics](https://wordpress.org/support/theme/sparkling/unresolved/)
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 * 1 reply
 * 2 participants
 * Last reply from: [ABCdatos](https://wordpress.org/support/users/abcdatos/)
 * Last activity: [5 years, 1 month ago](https://wordpress.org/support/topic/fatal-error-uncaught-error-undefined-constant-header/#post-14397956)
 * Status: not resolved