Python requests.post with Session returns 404 - works in postman

I am trying to submit POST data to the following link

http://epdsap.ap.gov.in/epdsAP/login/Submit.jsp

The flow here is, you GET the home page http://epdsap.ap.gov.in/ to get a cookie and then GET another link http://epdsap.ap.gov.in/epdsAP/login/FPSData.jsp to get a password that is embedded in the HTML response. Finally, you POST the data to http://epdsap.ap.gov.in/epdsAP/login/Submit.jsp to get another HTML response. I am getting 404 for the POST request and I am not sure why. I am using Session from requests to capture the cookies and reuse in subsequent requests.

The same works on Postman and I have compared the request headers.

import requests.utils
from bs4 import BeautifulSoup
s = requests.Session()
s.get('http://epdsap.ap.gov.in/')
r = s.get('http://epdsap.ap.gov.in/epdsAP/login/FPSData.jsp')
soup = BeautifulSoup(r.text, 'html.parser')
password = soup.find('input', {'name': 'j_password'}).get('value')
headers = {
        'Cache-Control': 'no-cache', 'Origin': 'chrome-extension://fdmmgilgnpjigdojojpjoooidkmcomcm',
        'DNT': '1',
        'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) '
                      'Chrome/64.0.3282.140 Safari/537.36',
        'Accept-Language': 'en-US,en;q=0.9,ta;q=0.8',
        'Accept': '*/*',
        'Connection': 'keep-alive'
}
payload = {'loginas': 'FsdData', 'j_username': 'guest', 'j_password': password.strip()}
r = s.post('http://epdsap.ap.gov.in/epdsAP/login/Submit.jsp', headers=headers, data=payload)
print(r.text)

I have even tried setting the "Content-Type" header to "text/plain;charset=UTF-8". The request headers are matching with Postman when viewed on Wireshark. I am not sure what I am missing.

Python version 3.6.4 Requests version 2.16.4

POSTMAN Request Headers that work

POSTMAN Request Headers that work

My Requests Headers that don't work

My Requests Headers that don't work