1.AndroidManifest.xml

<activity
            android:name=".activity.StartPage"
            android:screenOrientation="portrait">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

2.If that doesn’t solve the problem:

Delete all files in the following directory.

C:\Users\my_user_name\.AndroidStudio3.3\system\caches

View android studio version.

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