That port is already in use. code example
Example 1: django kill port
sudo fuser -k 8000/tcp
Example 2: port 8080 already in use
netstat -ano | findstr 8080
Example 3: port 8080 already in use
taskkill /F /pid 1088
sudo fuser -k 8000/tcp
netstat -ano | findstr 8080
taskkill /F /pid 1088