Check wp-config.php

The bottom of the standard wp-config.php file looks like this:

/**
* For developers: WordPress debugging mode.
*
* Change this to true to enable the display of notices during development.
* It is strongly recommended that plugin and theme developers use WP_DEBUG
* in their development environments.
*
* For information on other constants that can be used for debugging,
* visit the documentation.
*
* @link https://wordpress.org/support/article/debugging-in-wordpress/
*/
define( 'WP_DEBUG', false );

/* Add any custom values between this line and the "stop editing" line. */

//// WPf2b defines go here ////

/* That's all, stop editing! Happy publishing. */

/** Absolute path to the WordPress directory. */
if ( ! defined( 'ABSPATH' ) ) {
    define( 'ABSPATH', __DIR__ . '/' );
}

/** Sets up WordPress vars and included files. */
require_once ABSPATH . 'wp-settings.php';
​x
 
/**
* For developers: WordPress debugging mode.
*
* Change this to true to enable the display of notices during development.
* It is strongly recommended that plugin and theme developers use WP_DEBUG
* in their development environments.
*
* For information on other constants that can be used for debugging,
* visit the documentation.
*
* @link https://wordpress.org/support/article/debugging-in-wordpress/
*/
define( 'WP_DEBUG', false );
​
/* Add any custom values between this line and the "stop editing" line. */
​
//// WPf2b defines go here ////
​
/* That's all, stop editing! Happy publishing. */
​
/** Absolute path to the WordPress directory. */
if ( ! defined( 'ABSPATH' ) ) {
    define( 'ABSPATH', __DIR__ . '/' );
}
​
/** Sets up WordPress vars and included files. */
require_once ABSPATH . 'wp-settings.php';

The single most common reason WPf2b doesn't work as expected is that the define() statements are added too late in wp-config.php.

They absolutely must be added before the line that says:

/* That's all, stop editing! Happy publishing. */
xxxxxxxxxx
 
/* That's all, stop editing! Happy publishing. */

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