Dynamic dropdown doesn't populate with auto suggestions on https://www.nseindia.com/ when values are passed using Selenium and Python

I executed your test adding a few tweaks and ran the test as follows:

• Code Block:

  from selenium import webdriver        
  from selenium.webdriver.support.ui import WebDriverWait
  from selenium.webdriver.common.by import By
  from selenium.webdriver.support import expected_conditions as EC
  
  options = webdriver.ChromeOptions() 
  options.add_argument("start-maximized")
  options.add_experimental_option("excludeSwitches", ["enable-automation"])
  options.add_experimental_option('useAutomationExtension', False)
  driver = webdriver.Chrome(options=options, executable_path=r'C:\WebDrivers\chromedriver.exe')
  driver.get('https://www.nseindia.com/companies-listing/corporate-filings-actions')
  WebDriverWait(driver, 20).until(EC.element_to_be_clickable((By.XPATH, "//div[@id='Corporate_Actions_equity']//input[@placeholder='Company Name or Symbol']"))).send_keys("Reliance")
  

• Observation: Similar to your observation, I have hit the same roadblock with no results as follows:

Deep Dive

It seems the click() on the element with text as Get Data does happens. But while inspecting the DOM Tree of the webpage you will find that some of the <script> tag refers to JavaScripts having keyword akam. As an example:

• <script type="text/javascript" src="https://www.nseindia.com/akam/11/3b383b75" defer=""></script>
• <noscript><img src="https://www.nseindia.com/akam/11/pixel_3b383b75?a=dD02ZDMxODU2ODk2YTYwODA4M2JlOTlmOGNkZTY3Njg4ZWRmZjE4YmMwJmpzPW9mZg==" style="visibility: hidden; position: absolute; left: -999px; top: -999px;" /></noscript>

Which is a clear indication that the website is protected by Bot Manager an advanced bot detection service provided by Akamai and the response gets blocked.

Bot Manager

As per the article Bot Manager - Foundations:

Conclusion

So it can be concluded that the request for the data is detected as being performed by Selenium driven WebDriver instance and the response is blocked.

References

A couple of documentations:

• Bot Manager
• Bot Manager : Foundations

tl; dr

A couple of relevant discussions:

• Selenium webdriver: Modifying navigator.webdriver flag to prevent selenium detection
• Unable to use Selenium to automate Chase site login