Remove warning page in Ngrok server

I'm using Ngrok server (valet share) all things are fine... but when I visit the domain, I got the warning page ... I know there is a visit button to get into the website, but I need to remove it, cuz I have webhook send to my app and it will fail..

at the end of the page it says:

To remove this page:
    Set and send an ngrok-skip-browser-warning request header with any value.
    Or, set and send a custom/non-standard browser User-Agent request header.
    Or, please upgrade to any paid ngrok account.

I create a middleware to put ngrok-skip-browser-warning in the header but still got the page:

class NgrokMiddleware
{
    public function handle(Request $request, Closure $next)
    {
        $request->headers->set('ngrok-skip-browser-warning', '1231');

        return $next($request);
    }
}