Ionic App Capacitor error: namespace not specified in gradle.build

[DongJeff]

This is an Ionic Hybrid App using Capacitor. Here is my build.gradle, namespace is clearly specified, however when attempting to build, rebuild, or clean build this error returns:
Namespace not specified. Please specify a namespace in the module's build.gradle file like so:

android {
namespace 'com.example.namespace'
}

If the package attribute is specified in the source AndroidManifest.xml, it can be migrated automatically to the namespace value in the build.gradle file using the AGP Upgrade Assistant; please refer to https://developer.android.com/studio/build/agp-upgrade-assistant for more information.

Here is gradle.build:

apply plugin: 'com.android.application'

android {
namespace 'com.ionicthemes.ionic5fullapp'
testNamespace 'com.ionicthemes.ionic5testapp'
compileSdkVersion rootProject.ext.compileSdkVersion
defaultConfig {
applicationId "com.ionicthemes.ionic5fullapp"
minSdkVersion rootProject.ext.minSdkVersion
targetSdkVersion rootProject.ext.targetSdkVersion
versionCode 1
versionName "1.0"
testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}

repositories {
flatDir{
dirs '../capacitor-cordova-android-plugins/src/main/libs', 'libs'
}
}

dependencies {
implementation "androidx.core:core-splashscreen:$coreSplashScreenVersion"
implementation "androidx.coordinatorlayout:coordinatorlayout:$androidxCoordinatorLayoutVersion"
implementation fileTree(include: ['*.jar'], dir: 'libs')
implementation "androidx.appcompat:appcompat:$androidxAppCompatVersion"
implementation project(':capacitor-android')
testImplementation "junit:junit:$junitVersion"
androidTestImplementation "androidx.test.ext:junit:$androidxJunitVersion"
androidTestImplementation "androidx.test.espresso:espresso-core:$androidxEspressoCoreVersion"
implementation project(':capacitor-cordova-android-plugins')
implementation 'com.facebook.android:facebook-android-sdk:5.15.3'
}

apply from: 'capacitor.build.gradle'

try {
def servicesJSON = file('google-services.json')
if (servicesJSON.text) {
apply plugin: 'com.google.gms.google-services'
}
} catch(Exception e) {
logger.warn("google-services.json not found, google-services plugin not applied. Push Notifications won't work")
}

[jcesarmobile]

Looks like you upgraded to Gradle 8, Gradle 8 is not compatible with Capacitor 4, will be compatible with Capacitor 5.
You should downgrade Gradle until Capacitor 5 is ready, or you can start using Capacitor 5 already (but it's still in Beta)
Check the Capacitor 5 upgrade guide , but where it says npm i -D @capacitor/cli@latest do npm i -D @capacitor/cli@next instead.