How request http in Ionic 4 to Esp32

I have a app in Ionic 4 and using Esp32, so I connected in Router with app and get Id of devices

Now, I would like send ip through HttpClient and I know how to send this method

the URL should be “http://10.0.0.0/26/on” and my service I have

return this.http.get(${url} + ${eventClick});

But dont work, any solution ?