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// Block Non-Admins from Accessing Dashboard
function blockusers_init() {
  if ( is_admin() && ! current_user_can( 'administrator' ) && ! ( defined( 'DOING_AJAX' ) && DOING_AJAX ) ) {
      wp_redirect( home_url() );
      exit;
    }
}
add_action( 'init', 'blockusers_init' );