Is define created, if so what is its state?
Using a namespace? All php files declare the namespace at the top? Search all the files for “add_action”, confirm all uses include the namespace before the function name Search all the files for “add_shortcode”, confirm all uses include the namespace before the function name
All theme and plugin php files checks There must be no whitespace after the closing ?> tag of all theme and plugin PHP files.
Can often fix by pasting this line into wp-config.php file (or adjusting if already present) 256M is recommended for wordpress, less will often cause issues for some plugins etc.
Turn on wordpress debug mode In “/wp-config.php” find (or add) this define and set it to true: