I suspect that the reason is simply a wrong setup of your project.
To show you how simple it is to use our plugin to play a 360 video, here is a quick recording of a complete setup from scratch of a blank Unreal Engine project with the plugin enabled. The complete configuration requires less than 90 seconds.
We can provide support only for questions strictly related to the plugin and its API. For generic help with Unreal Engine, please rely on Epic resources or the community.