Maybe it's a technical limitation of the platform or system you're using. Sometimes there just isn't the capacity or functionality for multiple stories at once.
Well, one possible explanation is that the developers wanted to focus on the quality or consistency of a single story at a time. Another reason could be to prevent clutter or confusion. It's hard to say for sure without knowing the specific context or system in question.
It could be that the design of the feature doesn't support multiple photos to keep the story interface clean and simple. Or, there might be storage or processing constraints that prevent this functionality.
Maybe it's a rule of that platform to ensure quality control or avoid clutter.
Maybe it's a game rule to keep the balance or add challenge. You just have to work within that limit.
Perhaps the version of Story 2020 you're using has a bug. Another possibility is that your music file is corrupted or not in the correct location for it to be added to the story.
Maybe it's due to copyright issues. Some music has strict copyright protection, and using it without permission could lead to legal problems.
Maybe there's a technical glitch or the platform doesn't support it.
It could be due to technical limitations of the platform or to prevent spamming. Also, they might want to maintain a certain level of organization and readability for users.
It could be because there's not enough space or time within the story to incorporate it properly. Or perhaps it contradicts something that's already been established and would create confusion for the readers.
Maybe it's due to copyright issues. Some music is protected and can't be used without permission.
Maybe it's a technical glitch or a limitation of the platform you're using. Sometimes the software just doesn't support it.