Trying to add text to video, and the ouput only shows the final text, video never plays I have a project like this:

The 3D scene was just created it only contains a 2D text. it should play for 2 seconds, and then the video, but instead the text plays for the whole video. Even if I remove the text, then it will just be a greish video window, and the video I am trying to load never plays.
I need to close Blender, and add the video from fresh, but from the moment I play with a camera, my video is gone.
I am new to blender, so I guess there is something I am missing.
In the preview everything looks fine, and when I move my mouse around, the video looks fine. But when I click render, the output file will only contain the text.
I have also set the background of the text scene to transparent, and same behaviour.
Even If I remove that text scene, and then move the video to the start, then from that point on only that text scene will play. See:

If I start a project and just add this video, then it is fine.
In the project scene settings called Properties panel, make sure that you have Post Production > Sequencer active. Otherwise the VSE will not be rendered.