php - How to obtain response in Exception from Laravel into Kotlin

one text

I want to obtain the error messages from Laravel form request when i tried to register a new user in the system with invalid attributes, and use this messages on Kotlin to display them in the UI. The problem is when I tried to obtain this messages. For testing purpose first i just want to see the message and errors using Log.e():

response.body()?.message?.let { Log.e("error_message", it) }
response.body()?.validation_errors?.let { Log.e("error", it) }

First i overrided the failedValidation method on the custom Form request:

public function failedValidation(Validator $validator)
{
    $errors = $validator->errors(); // Array of errors.
    throw new HttpResponseException(response()->json([
        'message' => 'Validation error',
        'error' => (string)$errors->toJson()
    ], 422));
}

Here's the async call to the backend using retrofit in Kotlin:

val user = User(name, email, password, password_confirmation)
val call = request.register(user)

/** Async call */
call.enqueue(object : Callback<AuthResponse> {
    override fun onResponse(
        call: Call<AuthResponse>,
        response: Response<AuthResponse>
        ) {
            // It checks if status ~ 200
            if (response.isSuccessful) {
                //some code.
            } else {
                response.body()?.message?.let { Log.e("error_message", it) }
                response.body()?.validation_errors?.let { Log.e("error", it) }
            }
          }

          override fun onFailure(call: Call<AuthResponse>, e: Throwable) {
              //some code.
          }
    })
}

And the AuthResponse it defines like this:

data class AuthResponse(
    var error: String? = null,
    var message: String? = null,
    var user: User? = null,
    var token: String? = null,
    var token_expires_at: Date? = null,
    var validation_errors: String? = null
)