On your local host another service is already running on port 8080, probably another Mendix-app. Either check other Mendix Studio‘s that you have open on your pc and stop them running their app, or change the server-port of this app via App → Settings → Configuration → tab Server→ port.
Or kill the other process the rough way:
netstat -ano | findstr 8080 <- this will get you the processnumber that listens to port 8080 taskkill /F -pid <portnumber>
Change the port number from App → Settings → Configuration → tab Server→ port. Currently it must be 8080 and admin port 9090
change it with 8081 and admin port 9091. It should solve this issue.