How to decryption error body Retrofit in Android?

Question

I have a problem with the decryption error body from the response using Retrofit. I can get the error body from retrofit below:

val json = JSONObject(res.errorBody?.string())
val data = json.get("data").toString()

Noted: ErrorBody

{"data":"bsV9RBdM4GIDX6jvjvYdsUpkRMtl6JzhzOFiucZ+r78sbr3Tucjq9Idq7wL9qKTfDMPXpXcmubIKFzQzbomMNYoAlA9BTgdyA/6lkJQjAOk="}

After that, I need to decrypt object data to real data. Below is my encryption:

fun decrypt(encrypted: String?, iv: String, key: String): String {
            return try {
                val sKeySpec = generateKey(key)
                val ivKey = generateIV(iv)

                val cipher = Cipher.getInstance("AES/CBC/PKCS5Padding")
                cipher.init(Cipher.DECRYPT_MODE, sKeySpec, ivKey)
                val original = cipher.doFinal(Base64.decode(encrypted, Base64.NO_WRAP))
                return String(original, Charsets.UTF_8)
            } catch (e: Exception) {
                Timber.e("Error Decrypt: $e")
                ""
            }
}

Call encryption

val decryption = EncryptionUtils.decrypt(data, iv, key)
Timber.e("oooo: ${decryption}")

So when I log decryption, It shows like below:

ApiError(code=401, message=Unauthorized, data=null, errors=null)

But real data response from the server like below:

{"code" : 401, "message" : "Unauthorized",.....}

I didn't know what's the problem. Everyone, please help to resolve me that why it's return like this

ApiError(code=401, message=Unauthorized, data=null, errors=null)

I want it to return like below:

{"code" : 401, "message" : "Unauthorized",.....}