android studio have trouble with manifest merger

Question

I'm using android studio to develop an app. but today when I wanted to build my project , builder throw this error and I can't solve it.

Error:Execution failed for task ':app:processDebugManifest'.

com.android.manifmerger.ManifestMerger2$MergeFailureException: org.xml.sax.SAXParseException; lineNumber: 24; columnNumber: 10; Attribute name "l" associated with an element type "meta-data" must be followed by the ' = ' character.

I also create a new project but it throw this error again and don't build that project. and also can't Rebuild project and throw this error again and again .

manifest :

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="gsoosk.zad.far.yadavar">

    <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">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity android:name=".AddActivity" />
        <activity android:name=".ShowActivity" />
        <activity android:name=".RestartShowActivity" />
        <activity android:name=".NoEventActivity" />
        <activity android:name=".ListOfAllEventsActivity" />
    </application>

</manifest>

build.gardle :

apply plugin: 'com.android.application'

android {
    compileSdkVersion 26
    buildToolsVersion "26.0.0"
    defaultConfig {
        applicationId "gsoosk.zad.far.yadavar"
        minSdkVersion 15
        targetSdkVersion 26
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })

    compile 'com.android.support:appcompat-v7:26.+'
    compile 'com.android.support.constraint:constraint-layout:1.0.0-alpha7'
    testCompile 'junit:junit:4.12'
}