Short explanation: Your story is missing some necessary parts.
More info: Storybird is a site intended for original, narrative storytelling. What does that mean? Well, original = containing ideas from your own brain. Narrative = a written account of connected events. If your story or chapter does not contain any original work (like if it contains only pictures, with few or no words of your own), we may ask you to add more to it before it can be accepted into our public library. Likewise, if your story or chapter does not contain narrative elements like characters, setting, plot, conflict, or themes (for example, if it only contains lists, or is made up entirely of reviews of other books/movies/media), we may ask you to revise/change it before it can be accepted into our public library.
For more information and explanations about specific issues relating to our Guidelines, check the other topics in the Understanding Our Guidelines section of our Help/FAQ.