WhatsApp Business API - WhatsApp Flow

I am building WhatsApp Flow to retrieve orders. I am receiving the request and decrypting the message successfully. But I have trouble to encrypt response to WhatsApp. I got error: Invalid response from endpoint. I am using Python 3.9 and Pipedream. Some help?

See my encrypt code bellow:

from base64 import b64decode, b64encode from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes import json def handler(pd: "pipedream"):     # Getting the decrypted AES key and IV     aes_key_b64 = pd.steps["Decrypt_WhatsApp_Key"]["$return_value"]["decrypted_aes_key"]     iv_b64 = pd.steps["trigger"]["event"]["body"]["initial_vector"]     # Decoding AES key and base64 IV to bytes     aes_key = b64decode(aes_key_b64)     iv = b64decode(iv_b64)     # Preparing the inverted IV     iv_flipped = flip_iv(iv)     # Preparing response     response = {         "version": "3.0",         "screen": "SUCCESS",         "data": {             "extension_message_response": {                 "params": {                     "flow_token": pd.steps["Decrypt_WhatsApp_Message"]["$return_value"]["flow_token"],                     "status": pd.steps["shopify_developer_app"]["$return_value"]["orders"][0]["id"]                 }             }         }     }     response = json.dumps(response)     # Encrypting the response     cipher = Cipher(algorithms.AES(aes_key), modes.GCM(iv_flipped))     encryptor = cipher.encryptor()     encrypted = encryptor.update(response.encode("utf-8")) + encryptor.finalize() + encryptor.tag     encrypted_response = b64encode(encrypted).decode("utf-8")     # Response return     return {         "status": 200,         "body": encrypted_response,         "headers": {             "Content-Type": "application/json"         }     } def flip_iv(iv):     flipped_bytes = []     for byte in iv:         flipped_byte = byte ^ 0xFF         flipped_bytes.append(flipped_byte)     return bytes(flipped_bytes)```