I am using fluid boxes and have images and text captions set to Fade In Only. When I had a couple of images and one text caption it worked fine but as I add more text captions and then attempt to play the preview from that slide the stage goes white except for the two images. I'm not sure what other information needed to assist me but thought I would check to see if this is a known issue.
The "known issue" here may be that you have simply paused the timeline.
Take a look at the timeline of the slide. You may have added one or more interactive objects to the slide that are pausing the timeline. They will usually have a thin vertical line on their timeline layer that shows the point where they pause playback.
Does that look likely?
Can you insert a screenshot of the timeline please?