Android app closes immediately after launching
<p>I'm trying to finish off my app for publishing on the google play store so uploaded to the alpha testing phase. When trying to launch the app it closes immediately and this is the error that I receive:</p>

<pre><code>java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.FinalFrontier.MoonLanding/com.FinalFrontier.MoonLanding.MainActivity}: java.lang.ClassNotFoundException: Didn't find class "com.FinalFrontier.MoonLanding.MainActivity" on path: DexPathList[[zip file "/data/app/com.FinalFrontier.MoonLanding-1.apk"],nativeLibraryDirectories=[/data/app-lib/com.FinalFrontier.MoonLanding-1, /vendor/lib, /system/lib]]
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2192)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2316)
at android.app.ActivityThread.access$600(ActivityThread.java:150)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1298)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:213)
at android.app.ActivityThread.main(ActivityThread.java:5225)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:741)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:557)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.ClassNotFoundException: Didn't find class "com.FinalFrontier.MoonLanding.MainActivity" on path: DexPathList[[zip file "/data/app/com.FinalFrontier.MoonLanding-1.apk"],nativeLibraryDirectories=[/data/app-lib/com.FinalFrontier.MoonLanding-1, /vendor/lib, /system/lib]]
at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:53)
at java.lang.ClassLoader.loadClass(ClassLoader.java:501)
at java.lang.ClassLoader.loadClass(ClassLoader.java:461)
at android.app.Instrumentation.newActivity(Instrumentation.java:1061)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2183)
... 11 more
</code></pre>

<p>​
This is my first ever app and I'm pretty new to this so any help would be greatly appreciated. I've read the documentation and searched the errors online however can't seem to get any of the solutions to work. Here's a copy of my android manifest.</p>

<pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
&lt;manifest xmlns:android="http://schemas.android.com/apk/res/android" android:versionCode="2" android:versionName="1.1" package="com.FinalFrontier.MoonLanding" android:installLocation="preferExternal"&gt;
&lt;application android:icon="@drawable/app_icon" android:label="@String/app_name" android:debuggable="false" android:isGame="true" android:banner="@drawable/app_banner"&gt;
&lt;activity android:configChanges="fontScale|keyboard|keyboardHidden|locale|mnc|mcc|navigation|orientation|screenLayout|screenSize|smallestScreenSize|uiMode|touchscreen" android:label="@String/app_name" android:name="com.FinalFrontier.MoonLanding.CustomActivity"&gt;
&lt;intent-filter&gt;
&lt;action android:name="android.intent.action.MAIN" /&gt;
&lt;category android:name="android.intent.category.LAUNCHER" /&gt;
&lt;category android:name="android.intent.category.LEANBACK_LAUNCHER" /&gt;
&lt;/intent-filter&gt;
&lt;/activity&gt;
&lt;activity android:configChanges="fontScale|keyboard|keyboardHidden|locale|mnc|mcc|navigation|orientation|screenLayout|screenSize|smallestScreenSize|uiMode|touchscreen" android:hardwareAccelerated="true" android:name="com.unity3d.ads.android.view.UnityAdsFullscreenActivity" android:theme="@android:style/Theme.NoTitleBar.Fullscreen" xmlns:tools="http://schemas.android.com/tools" tools:ignore="UnusedAttribute" /&gt;
&lt;/application&gt;
&lt;uses-permission android:name="android.permission.INTERNET" /&gt;
&lt;uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" /&gt;
&lt;uses-permission android:name="android.permission.ACCESS_WIFI_STATE" /&gt;
&lt;uses-permission android:name="com.android.vending.BILLING" /&gt;
&lt;uses-sdk android:minSdkVersion="9" android:targetSdkVersion="23" /&gt;
&lt;uses-feature android:glEsVersion="0x00020000" /&gt;
&lt;uses-feature android:name="android.hardware.sensor.accelerometer" android:required="false" /&gt;
&lt;uses-feature android:name="android.hardware.touchscreen" android:required="false" /&gt;
&lt;uses-feature android:name="android.hardware.touchscreen.multitouch" android:required="false" /&gt;
&lt;uses-feature android:name="android.hardware.touchscreen.multitouch.distinct" android:required="false" /&gt;
&lt;/manifest&gt;
</code></pre>

<p>Anybody got any ideas? Thanks in advance.</p>