The cause is your security settings of the browser. You can try http://localhost:8080 instead or you might have to edit the settings of your browser to allow the connection. Also you might be able to continue anyway
Hope this helps!
Hello Shrinithi, does your computer have a Firewall or a Antivirus Software that is blocking the ports 8080 and 8090?
Also on windows machine when you first time run the mendix app it might have popped up Firewall exception message to allow receiving traffic to application(your mendix app) did you by any chance clicked on dont allow or canceled that popup?
1 thing you can do is momentarily disable all Security software (may be switch of internet too to safeguard yourself) and then see if the app works.
Did you try from another machine?