Unable to get response from FreshDesk API in proxy mode {"code" : "invalid_credentials", "message" : "You need to be logged in to perform action"}

So I'm using FreshDesk API and able to get the response using request module, But whenever I'm using proxy servers I'm unable to get the response.

import base64
import requests
import os
from requests.auth import HTTPBasicAuth
import ssl
method = "get"
url = "https://mycompanydomain.freshdesk.com/api/v2/tickets"
apiKey = "XXXXXXXXX"
secret = "x"
os.environ["REQUESTS_CA_BUNDLE"] = "Path to CA Certs"
auth = HTTPBasicAuth(apiKey, secret)
rsp = requests.request(method, url, headers=None, auth=auth)
print(rsp.text)

But whenever I'm using the proxy server in my organization, I'm getting an error message as {"code":"invalid_credentials","message":"You have to be logged in to perform this action."}

Code which I'm using for the proxy servers

import base64
import requests
import http.client
import urllib.parse
method = "get"
apiKey = "XXXXXXXX"
secret = "x"
url = "https://mycompanydomain.freshdesk.com/api/v2/tickets"
cred= '{}:{}'.format(apiKey, secret)
cred =  base64.b64encode(cred.encode('utf-8')).decode('utf-8')
authorization_headers = {
        'Proxy-Authorization': 'Basic {}'.format(cred)
}
conn = http.client.HTTPSConnection("11.125.250.121", 3128)
conn.set_tunnel("mycompanydomain.freshdesk.com", headers = authorization_headers)
headers = { 'Content-Type' : 'application/json' }
conn.request("GET", "/api/v2/tickets",headers = headers)
res = conn.getresponse()
data = res.read()
print(data.decode("utf-8"))

FreshDesk API Docs for using their API

curl -v -u abcdefghij1234567890:X -H "Content-Type: application/json" -X GET 'https://domain.freshdesk.com/api/v2/tickets'

Any possible way to resolve this error?

from Unable to get response from FreshDesk API in proxy mode {"code" : "invalid_credentials", "message" : "You need to be logged in to perform action"}