airflow standalone problem fix: The webserver is already running under PID 3244

problems

with airflow standalone to start server with error:
The webserver is already running under PID 3244.

Try to list full server listening in local server:
sudo lsof -i tcp:8082

Get output result:
python3.9 3244 guangqianglu 9u IPv4 0x5b88a0de83856537 0t0 TCP *:us-cli (LISTEN)

Then kill the port for 3244:
kill -9 3244.

then restart airflow server:
airflow webserver -p 8082