Android Studio `Plugin with id 'com.android.application' not found`

I'm getting the following error in my Android Studio project. It was running just fine until I closed Android Studio and re-opened it. The project uses both Kotlin and Java -- i'm not sure if that's worth mentioning, but again, it was working just fine. Closing and opening the project back up caused this to happen:

apply plugin: 'com.android.application'

apply plugin: 'com.google.protobuf'

apply plugin: 'kotlin-android'

apply plugin: 'kotlin-android-extensions'

apply plugin: 'kotlin-kapt'

apply plugin: 'kotlinx-serialization'

android {
    compileSdkVersion 29
    buildToolsVersion "29.0.3"
    packagingOptions {
        pickFirst 'org/eclipse/jetty/http/encoding.properties'
    }
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
    kotlinOptions {
        jvmTarget = "1.8"
    }
    defaultConfig {
        applicationId "com.example.myapplication"
        minSdkVersion 28
        targetSdkVersion 29
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    def room_version = "2.2.4"
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'com.android.volley:volley:1.1.1'
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
    implementation 'androidx.appcompat:appcompat:1.1.0'
    implementation 'androidx.room:room-ktx:2.2.4'
    kapt "androidx.room:room-compiler:2.2.4"
    kapt "androidx.room:room-compiler:$room_version"
    implementation "androidx.room:room-runtime:$room_version"
    implementation 'androidx.core:core-ktx:1.2.0'
    implementation "com.google.zxing:core:3.3.0"
    implementation "com.google.protobuf:protobuf-lite:3.0.0"
    implementation 'com.google.zxing:javase:3.3.0'
    implementation 'io.javalin:javalin:3.7.0'
    implementation "androidx.room:room-ktx:$room_version"
    implementation 'org.slf4j:slf4j-simple:1.7.26'
    implementation "com.fasterxml.jackson.core:jackson-databind:2.10.1"
    implementation 'com.google.code.gson:gson:2.8.6'
    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
    implementation 'com.google.android.material:material:1.0.0'
    implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
    implementation "org.jetbrains.kotlinx:kotlinx-serialization-runtime:0.11.0"
    implementation "com.fasterxml.jackson.module:jackson-module-kotlin:2.10.1"
    testImplementation 'junit:junit:4.12'
    implementation 'com.android.support:recyclerview-v7:28.0.0'
    testImplementation "androidx.room:room-testing:$room_version"
    androidTestImplementation 'androidx.test.ext:junit:1.1.1'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'
}