Android project cannot build with gradle after importing a module

I created an android app and I wanted to include the vokaturi module. I changed the vokaturi.gradle file with "com.android.library" and I included ":vokaturi" module in the settings.gradle file and in the main app module I added implementation project(':vokaturi') When I try to syncronised main app module I get the error

Could not find :OpenVokaturi-Android:.
Required by:
    project :app > project :vokaturi
Search in build.gradle files  

This is how my main app.gradle file looks like.

    apply plugin: 'com.android.application'
    android {
        compileSdkVersion 28
    defaultConfig {
        applicationId "com.example.afinity"
        minSdkVersion 21
        targetSdkVersion 28
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
    }
    dependencies {
    implementation fileTree(include: ['*.jar'], dir: 'libs')
    implementation 'com.android.support:appcompat-v7:28.0.0'
    implementation 'com.android.support.constraint:constraint-layout:1.1.3'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test:runner:1.0.2'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'

    implementation project(':vokaturi')
    }

And this is how the vokaturi.gradle file looks like

apply plugin: 'com.android.library'

android {
    compileSdkVersion 28
    defaultConfig {

        minSdkVersion 21
        targetSdkVersion 28
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}
repositories {
    flatDir {
        dirs 'libs/aars'
    }
}
dependencies {
    implementation(name: 'OpenVokaturi-Android', ext: 'aar')
    implementation fileTree(include: ['*.jar'], dir: 'libs')
    implementation 'com.android.support:appcompat-v7:28.0.0'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test:runner:1.0.1'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.1'
}

I do not know what I do wrong...I am new at android, thank you all for any help

The default name of the file is probably - OpenVokaturi-3-0-android.aar and not OpenVokaturi-Android which is why you're getting that error. Also this -

implementation(name: 'OpenVokaturi-3-0-android.aar', ext: 'aar')

should not be in your vokaturi module but rather in your app.gradle file. Add that line to your app gradle file and then include vokaturi directly as an aar file.