Go to project Setting → go to configuration window → double click a pop up window opens
→ go to server tab → you will be able to see run time port and admin port → change your admin port
eg:9090 and change your runtime port eg:8087
hope it helps!
Rebooting your computer will solve it, but if you are looking for a better way open a command-prompt and try these commands:
netstat -ano | find ":8080"
TASKKILL /PID <processid> -f