Python Selenium: How to avoid being detected/ blocked?

The error messageI try to extract data from the below website. But when the selenium click the "search" button (the last step of the code), error was returned, it seems blocked by the server (It is totally alright when I access the website manually. But when I use automated Chrome browser, the attached error message was returned when I click the "search" button). How should I get around this?

from selenium import webdriver
from selenium.webdriver.chrome.service import Service
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait 
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.chrome.options import Options
import time

ser = Service(r"C:\Users\shekc\Documents\chromedriver.exe")
options = webdriver.ChromeOptions()

options.add_experimental_option("excludeSwitches", ["enable-automation"])
options.add_experimental_option('useAutomationExtension', False)
options.add_argument("–Referer=https://www.dahsing.com/jsp/fundPlatform/index_e.jsp")
options.add_argument("user-agent=Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.106 Safari/537.36")
driver = webdriver.Chrome(options=options, service=ser)

url = "https://www.dahsing.com/jsp/fundPlatform/risk_warning_e.jsp"
driver.get(url)
time.sleep(3)

# click "Agree"
driver.find_element(By.LINK_TEXT,"Agree").click()
driver.switch_to.default_content()
driver.switch_to.frame(1)

# return the # Fund house
from selenium.webdriver.support.ui import Select
Select =Select(driver.find_element(By.XPATH,'//*[@id="mainContent_ddlFundHouse"]'))
FH_No=len(Select.options)

# select " all per page"
from selenium.webdriver.support.ui import Select
Select =Select(driver.find_element(By.XPATH,'//*[@id="mainContent_ddlPageNumber"]'))
Select.select_by_index(len(Select.options)-1)

Select =Select(driver.find_element(By.XPATH,'//*[@id="mainContent_ddlFundHouse"]'))
    Select.select_by_index(1)
    FH_name=Select.first_selected_option.text
    # click "Search"
    driver.find_element(By.LINK_TEXT,"Search").click()