Why I'm getting PayPal Android Native Checkout SDK - invalid client_id or redirect_uri

I'm using the new Native Checkout SDK for Android with Kotlin and I've been following every step in the documentation but this keeps happening and I don't know why. I'm trying also PayPal Android Native Checkout SDK - invalid client_id or redirect_uri, and CHECKOUT_ERROR but but it didn't work for me.

build.girdle :

plugins {
    id 'com.android.application'
    id 'kotlin-android'
    id 'kotlin-android-extensions'
}

android {
    compileSdkVersion 30
    buildToolsVersion "30.0.2"

    defaultConfig {
        applicationId "com.example.paypalkotlin"
        minSdkVersion 23
        targetSdkVersion 30
        versionCode 1
        versionName "1.0"

        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
    kotlinOptions {
        jvmTarget = '1.8'
    }
}

dependencies {

    implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
    implementation 'androidx.core:core-ktx:1.2.0'
    implementation 'androidx.appcompat:appcompat:1.3.0'
    implementation 'com.google.android.material:material:1.3.0'
    implementation 'androidx.constraintlayout:constraintlayout:2.0.4'
    implementation('com.paypal.checkout:android-sdk:0.2.0')
    testImplementation 'junit:junit:4.+'
    androidTestImplementation 'androidx.test.ext:junit:1.1.2'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.3.0'
}

build girdle

// Top-level build file where you can add configuration options common to all sub-projects/modules.
buildscript {
    ext.kotlin_version = "1.3.72"
    repositories {
        google()
        jcenter()
    }
    dependencies {
        classpath "com.android.tools.build:gradle:4.1.3"
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        google()
        jcenter()
        mavenCentral()
        // This private repository is required to resolve the Cardinal SDK transitive dependency.
        maven {
            url  "https://cardinalcommerceprod.jfrog.io/artifactory/android"
            credentials {
                // Be sure to add these non-sensitive credentials in order to retrieve dependencies from the private repository.
              
                username "paypal_sgerritz"
                password "AKCp8jQ8tAahqpT5JjZ4FRP2mW7GMoFZ674kGqHmupTesKeAY2G8NcmPKLuTxTGkKjDLRzDUQ"
            }
        }

    }
}


task clean(type: Delete) {
    delete rootProject.buildDir
}

Manifest

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.paypalkotlin">
    <uses-permission android:name="android.permission.INTERNET"/>

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.PaypalKotlin">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

layout

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <com.paypal.checkout.paymentbutton.PayPalButton
        android:id="@+id/payPalButton"
        android:layout_width="100dp"
        android:layout_height="wrap_content"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

Activity

package com.example.paypalkotlin

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.util.Log

import com.paypal.checkout.PayPalCheckout
import com.paypal.checkout.approve.OnApprove
import com.paypal.checkout.config.CheckoutConfig
import com.paypal.checkout.config.Environment
import com.paypal.checkout.config.SettingsConfig
import com.paypal.checkout.createorder.CreateOrder
import com.paypal.checkout.createorder.CurrencyCode
import com.paypal.checkout.createorder.OrderIntent
import com.paypal.checkout.createorder.UserAction
import com.paypal.checkout.order.Amount
import com.paypal.checkout.order.AppContext
import com.paypal.checkout.order.Order
import com.paypal.checkout.order.PurchaseUnit
import kotlinx.android.synthetic.main.activity_main.*

class MainActivity : AppCompatActivity() {

    val YOUR_CLIENT_ID = "AVxCKg9vnFKxNXLU5LLylEOnGCnsG8UiN300FlmY37zI4oKdrpyiuR_zutUn77rKSVxC377x0jM_uCPk";
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        val config = CheckoutConfig(
                application = application,
                clientId = YOUR_CLIENT_ID,
                environment = Environment.SANDBOX,
                returnUrl = "${BuildConfig.APPLICATION_ID}://paypalpay",
                currencyCode = CurrencyCode.USD,
                userAction = UserAction.PAY_NOW,
                settingsConfig = SettingsConfig(
                        loggingEnabled = true
                )
        )

        PayPalCheckout.setConfig(config)
        payPalButton.setup(
                createOrder = CreateOrder { createOrderActions ->
                    val order = Order(
                            intent = OrderIntent.CAPTURE,
                            appContext = AppContext(
                                    userAction = UserAction.PAY_NOW
                            ),
                            purchaseUnitList = listOf(
                                    PurchaseUnit(
                                            amount = Amount(
                                                    currencyCode = CurrencyCode.USD,
                                                    value = "10.00"
                                            )
                                    )
                            )
                    )
                    createOrderActions.create(order)
                },

                onApprove = OnApprove { approval ->
                    approval.orderActions.capture { captureOrderResult ->
                        Log.i("CaptureOrder", "CaptureOrderResult: $captureOrderResult")
                    }
                }
        )

    }

}