Rendering Issues - Only exporting the background and not the animation

I've created an animation where it spells out the PNG file but when it comes to rendering and exporting this creation, it's only exporting the black compostion background and not the animation i've made within that composition. When I add it to the rendering queue the preview is also just the black background and not the creation itself. I can't find anything online to solve this issue, will be really thankful if someone can help me solve this! 

I've also have attached a screenshot of my AE project and how it's just a black screen when i've exported it. 

Thanks!