Android Studio XML Drawable Selector Not Displaying An Item

I'm having an issue with my custom checkbox in that the selector does not show the white rounded rectangle with a yellow stroke when unchecked?

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://ift.tt/nIICcg">
    <item android:state_checked="true">
        <layer-list>
            <item>
                <shape android:shape="rectangle">
                    <solid android:color="#ffffff" />
                    <stroke android:width="4px" android:color="@color/colourAccent" />
                    <size android:width="36dp" android:height="36dp" />
                    <corners android:radius="2dp" />
                </shape>
            </item>
            <item>
                <vector
                    android:width="24dp"
                    android:height="24dp"
                    android:viewportWidth="24.0"
                    android:viewportHeight="24.0">
                    <path
                        android:fillColor="@color/colourAccent"
                        android:pathData="M9,16.17L4.83,12l-1.42,1.41L9,19 21,7l-1.41,-1.41z"/>
                </vector>
            </item>
        </layer-list>
    </item>
    <item>
        <shape android:shape="rectangle">
            <solid android:color="#ffffff" />
            <stroke android:width="4px" android:color="@color/colourAccent" />
            <corners android:radius="2dp" />
            <size android:width="36dp" android:height="36dp" />
        </shape>
    </item>
</selector>

For the life of me I am unable to figure out the issue nor discover the fix