try this in your php file
ini_set("log_errors", 1);
ini_set("error_log",$_SERVER['DOCUMENT_ROOT']."/logs/php-error.log");
Give write permission to the folder logs and its file, then check the file in logs folder.
error_log:error_log
error_log
not has correct path, set a correct path like below
log_errors = On
error_log = "C:\xampp\php\logs\php_error_log"