SMS using twilio from mobile app not working - gradle

Question

As per the guidelines in this tutorial.
I've completed everything. But it's not working. No errors are occurring. I don't know where to check for the issues. Please can someone help me with a solution or at least where to look for issues?
Please find below manifest file
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:dist="http://schemas.android.com/apk/distribution"
package="uhnm.stroke.strokeapp_secondscreen">
<dist:module dist:instant="true" />
<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/AppTheme"
android:usesCleartextTraffic="true">
<activity android:name=".NIHSSActivityPage4" android:windowSoftInputMode="adjustPan"/>
<activity android:name=".TeamsDisplay" android:windowSoftInputMode="adjustPan" />
<activity android:name=".imageActivity" android:windowSoftInputMode="adjustPan" />
<activity android:name=".timesActivity" />
<activity android:name=".configurationActivity" />
<activity android:name=".addConsultants" />
<activity android:name=".NIHSSActivityFinalPage"android:windowSoftInputMode="adjustPan" />
<activity android:name=".NIHSSActivityPage3" android:windowSoftInputMode="adjustPan" />
<activity android:name=".NIHSSActivityPage2" android:windowSoftInputMode="adjustPan" />
<activity android:name=".MainActivity" android:windowSoftInputMode="adjustPan" />
<activity android:name=".EnterBrainTracker" />
<activity android:name=".NIHSSActivity" android:windowSoftInputMode="adjustPan" />
<activity
android:name=".signIn"
android:windowSoftInputMode="adjustPan">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<service
android:name=".MyFirebaseMessagingService"
android:exported="false">
<intent-filter>
<action android:name="com.google.firebase.MESSAGING_EVENT" />
</intent-filter>
</service>
<meta-data
android:name="strokeapp.messaging.default_notification_channel_id"
android:value="#string/default_notification_channel_id" />
</application>
</manifest>
Here the app gradle file:
apply plugin: 'com.android.application'
apply plugin: 'com.google.gms.google-services'
android {
compileSdkVersion 29
buildToolsVersion "29.0.2"
//useLibrary 'org.apache.http.legacy'
defaultConfig {
applicationId "uhnm.stroke.strokeapp_secondscreen"
minSdkVersion 16
targetSdkVersion 29
versionCode 1
versionName "1.0"
testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
multiDexEnabled true
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
}
}
packagingOptions
{
exclude 'META-INF/DEPENDENCIES'
}
}
dependencies {
implementation fileTree(dir: 'libs', include: ['*.jar'])
implementation 'com.android.support:multidex:1.0.3'
implementation 'androidx.appcompat:appcompat:1.1.0'
implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
implementation 'com.google.firebase:firebase-database:19.2.0'
implementation 'com.google.firebase:firebase-storage:19.1.0'
implementation 'com.google.firebase:firebase-auth:19.1.0'
implementation 'com.google.firebase:firebase-core:17.2.1'
implementation 'com.google.firebase:firebase-messaging:20.0.0'
testImplementation 'junit:junit:4.12'
androidTestImplementation 'androidx.test:runner:1.2.0'
androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'
implementation 'com.android.support:support-annotations:28.0.0'
implementation 'com.google.android.material:material:1.1.0-alpha10'
implementation group: "com.twilio.sdk", name: "twilio", version: "7.44.0"
implementation 'com.squareup.okhttp3:okhttp:4.2.1'
}