Notice: Undefined variable: filebird_activation_error in C:\xampp\htdocs\wp-content\plugins\filebird-pro\views\particle\activation_fail.php on line 5

Fatal error: Uncaught Error: Call to undefined function apply_filters() in C:\xampp\htdocs\wp-content\plugins\filebird-pro\views\particle\activation_fail.php:6 Stack trace: #0 {main} thrown in C:\xampp\htdocs\wp-content\plugins\filebird-pro\views\particle\activation_fail.php on line 6