Encrypting AES 256 CBC using python and decrypting using PHP

This here is successfully send to the endpoint with encrypted data using aes-256-cbc. The http_status: 200

scenarioId = 123
useCaseId = 1
keyword = "test"
dataDump = "Test"

iv = b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
key = "RPAstudio01"

url = "http://localhost:8080/raven_event/"

header = {'Authorization' : 'Basic UlBBU3R1ZGlvOlJQQXN0dWRpb25vMQ==',
                'Content-Type' : 'application/json',
                'Accept' : 'application/json'
                }

payload = {
                    "useCaseId":useCaseId,
                    "scenarioId": scenarioId,
                    "keyword": keyword,
                    "dataDump": dataDump
                }

json_payload = json.dumps(payload)

encyrption = AESCipher.AESCipherx(key)
x = encyrption.encrypt(json_payload, iv)
print(x)
request = requests.post(url, data=json_payload, headers=header)
print(request.status_code)

This is the encryption code process.

import base64
import hashlib
from Crypto import Random
from Crypto.Cipher import AES

class AESCipherx(object):

def __init__(self, key): 
    self.bs = AES.block_size
    self.key = hashlib.sha256(key.encode()).digest()

def encrypt(self, raw, iv):
    #private_key = hashlib.sha256(private_key.encode("utf-8")).digest()
    raw = self._pad(raw)
    #iv = Random.new().read(AES.block_size)
    cipher = AES.new(self.key, AES.MODE_CBC, iv)
    #return base64.b64encode(cipher.encrypt(raw.encode()))
    print(cipher)
    x = base64.b64encode(iv + cipher.encrypt(raw.encode()))
    print(x)
    return base64.b64encode(cipher.encrypt(raw.encode()))


def _pad(self, s):
        return s + (self.bs - len(s) % self.bs) * chr(self.bs - len(s) % self.bs)

My php code for decrypting the sent data. my problem here is when I decrypt the value is all null:

<?php
function decrypt($encrypted){
    $password = "RPAstudio01";
    $method = 'aes-256-cbc';
    $key = substr(hash('sha256', $password, true), 0, 32);
    $iv = chr(0x0) . chr(0x0) . chr(0x0) . chr(0x0) . chr(0x0) . chr(0x0) . chr(0x0) . chr(0x0) . chr(0x0) . chr(0x0) . chr(0x0) . chr(0x0) . chr(0x0) . chr(0x0) . chr(0x0) . chr(0x0);
    $decrypted = openssl_decrypt(base64_decode($encrypted), $method, $key, OPENSSL_RAW_DATA, $iv);

    return $decrypted;
}

This is the result with null values in JSON Format. Can anyone enlighten me why is this happening? Is my IV wrong on the php side? Or is it in python? Or maybe theres something with the code i'm doing wrong? Or missing something?

{
    "useCaseId": null,
    "scenarioId": null,
    "keyword": null,
    "dataDump": null
}