Flask application KeyError "state" google oauth

Question

I am try to implement signup with google in my Flask application it's working fine on localhost but when we deploy the code on our AWS I always get internal server error which says keyerror : "state", I am using google oauth library, soucre: https://www.youtube.com/watch?v=FKgJEfrhU1E&t=71s

        signup = Blueprint("signup" ,__name__)
        mail = Mail()
        GOOGLE_CLIENT_ID = "HIDDEN"
        client_secrets_file = os.path.join(pathlib.Path(__file__).parent, "client_secret.json")
        flow = Flow.from_client_secrets_file(client_secrets_file = client_secrets_file, 
        scopes = ["https://www.googleapis.com/auth/userinfo.profile", "https://www.googleapis.com/auth/userinfo.email", "openid"],
        redirect_uri = "http://45-79-245-94.ip.linodeusercontent.com:5000/signup/callback") #once you deploy this code change the IP!

        os.environ["OAUTHLIB_INSECURE_TRANSPORT"] = "1"


        # function to generate OTP
     




       

        @signup.route("/google", methods=['GET', 'POST'])
        @cross_origin(allow_headers=['Content-Type', 'x-access-token', 'Authorization'])
        def Google_Login():
            if request.method == 'GET':
                authorization_url, state = flow.authorization_url()
                session["state"] = state
                return redirect(authorization_url)
            else:
                user_data = request.get_json() 
                email = user_data["email"]
                username = user_data["username"]
                gender = user_data["gender"]
                name = user_data["name"]
                location = user_data["location"]
                website = user_data["website"]
                prof_pic_url = user_data["prof_pic_url"]
                date_of_birth = user_data["date_of_birth"]
                isfound = Database.User.find_one({"username": username})
                creation_date = datetime.datetime.now()
                if isfound == None:
                    following = []
                    followers = []
                    Database.User.insert_one({
                        "email": email,
                        "name": name,
                        "username": username,
                        "date_of_birth": date_of_birth,
                        "gender": gender,
                        "creation_date": creation_date,
                        "admin": False,
                        "bio": None,
                        "webiste": website,
                        "location": location,
                        "prof_pic_url": prof_pic_url,
                        "cover_pic_url": "https://i.pinimg.com/564x/a2/64/b4/a264b464b6fd6138d972448e19ba764d.jpg",
                        "following_count": 0,
                        "followers_count": 0,
                        "following": following,
                        "followers": followers,
                        "tweet_count": 0 
                        })

                    db_response = Database.User.find_one({"username": username})
                    user_id = db_response["_id"]
                    user_id = str(user_id)

                    token = jwt.encode({'_id': user_id, 'admin': False, 'exp': datetime.datetime.utcnow() + datetime.timedelta(minutes= 525600)}, "SecretKey1911")
                    return jsonify({"message": "google user created",
                    "token": token,
                    "admin": False,
                    "user_id": user_id}),400
            
                else:
                    return jsonify({"messsage": "username exists"}),400



        @signup.route("/callback", methods=['GET'])
        @cross_origin(allow_headers=['Content-Type', 'x-access-token', 'Authorization'])
        def callback():
            flow.fetch_token(authorization_response=request.url)
            if not session["state"] == request.args["state"]:
                abort(500)  # State does not match!

            credentials = flow.credentials
            request_session = requests.session()
            cached_session = cachecontrol.CacheControl(request_session)
            token_request = google.auth.transport.requests.Request(session=cached_session)
            

            id_info = id_token.verify_oauth2_token(
                id_token=credentials._id_token,
                request=token_request,
                audience=GOOGLE_CLIENT_ID
            )
            isfound = Database.User.find_one({"email": id_info['email']})

            
            if isfound == None:
                isfound = Database.User.find_one({"username": id_info["given_name"]})
                if isfound == None:
                    username = id_info["given_name"]
                else:
                    while (1):
                    OTP = generateOTP()
                    username = id_info["given_name"] + OTP
                    if Database.User.find_one({"username": username}) == None:
                        break

                return jsonify({"message": "user verified",
                "prof_pic_url": id_info["picture"],
                "name": id_info["given_name"],
                "recommended_user_name": username})


        
            
            else:
                db_response = Database.User.find_one({"email": id_info["email"]})
                user_id = db_response["_id"]
                user_id = str(user_id)
                token = jwt.encode({'_id': user_id, 'admin': False, 'exp': datetime.datetime.utcnow() + datetime.timedelta(minutes= 525600)}, "SecretKey1911")
                return jsonify({"message": "user exists",
                "token": token,
                "admin": False,
                "user_id": user_id}),400
            



      


            
            


            

here is the error I get from server side: