selenium.common.exceptions.WebDriverException: Message: unknown error: net::ERR_CONNECTION_RESET

I am new to those technologies.
My OS is ubuntu-18.04 and using anaconda to create a virtual environment with pip installation with all necessary package. I also install Chrome and chromedriver with the same version to run the selenium. I also create a test.service under /etc/systemd/system

I cann't post image in stackoverflow.
The problem can be seen in screenshot with command (sudo systemctl status test)

gunicorn[25770]: File "/home/anaconda/port8788/hct/hct_information.py", line 21, in testDriver
gunicorn[25770]: driver.get(url)
gunicorn[25770]: File "/home/chaoyang/anaconda3/envs/selenium/lib/python3.9/site-packages/selenium/webdriver/remote/webdriver.py", line 333, in get
gunicorn[25770]: self.execute(Command.GET, {'url': url})
gunicorn[25770]: File "/home/chaoyang/anaconda3/envs/selenium/lib/python3.9/site-packages/selenium/webdriver/remote/webdriver.py", line 321, in execute
gunicorn[25770]: self.error_handler.check_response(response)
gunicorn[25770]: File "/home/chaoyang/anaconda3/envs/selenium/lib/python3.9/site-packages/selenium/webdriver/remote/errorhandler.py", line 242, in check_response
gunicorn[25770]: raise exception_class(message, screen, stacktrace) gunicorn[25770]: selenium.common.exceptions.WebDriverException: Message: unknown error: net::ERR_CONNECTION_RESET gunicorn[25770]: (Session info: headless chrome=86.0.4240.183)

My Flask Code is below:

import flask
from flask import request
import argparse
from hct import hct_information as hct

app = flask.Flask(__name__)

@app.route("/test")
def test():
    return hct.testDriver('https://www.google.com/')

if __name__ == "__main__":
    app.run(debug=True, host='0.0.0.0')

My selenium Code is below:

from selenium import webdriver
from selenium.webdriver.chrome.options import Options
from selenium.webdriver.common.keys import Keys
from selenium.common.exceptions import NoSuchElementException
import time

def testDriver(url):
options = Options()
options.binary_location = '/usr/bin/google-chrome'
options.add_argument('--headless')
options.add_argument('--disable-gpu')
options.add_argument('--no-sandbox') #for linux avoid chrome not started
options.add_experimental_option("excludeSwitches", ['enable-automation'])
options.add_argument('--user-agent="Mozilla/5.0 (Windows Phone 10.0; Android 4.2.1; Microsoft; Lumia 640 XL LTE) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/42.0.2311.135 Mobile Safari/537.36 Edge/12.10166"')
#options.add_argument('window-size=500*250')
driver = webdriver.Chrome(executable_path=('/usr/bin/chromedriver'), options=options)
driver.get(url)
time.sleep(1)

title = driver.title
driver.close()
return title

It should be a simple program. Unfortunately, when I test separately using python to run the flask api everything is fine, even with gunicorn --bind 0.0.0.0:5000 test:app is also run without above message. Any Idea where I done things incorrectly????