Well, sometimes FB has certain rules and policies regarding music usage in stories. It could be that the music you chose doesn't comply with their copyright terms. Also, check if your internet connection is stable as that can affect the ability to add music.
It could be because of a problem with the Facebook app itself. Try uninstalling and reinstalling the app. This can often fix glitches that prevent you from adding music.
Maybe there's a glitch in the FB app. Sometimes these things happen and you just need to wait for an update to fix it.
Maybe there's a technical glitch or your app doesn't support that feature.
Maybe there's a compatibility issue or your app doesn't support that feature.
It could be that you don't have the proper permissions or your music file format isn't compatible. Sometimes, the platform's rules might also prevent it.
Maybe there were some technical glitches or compatibility issues with the platform you were using back then.
Maybe there were some technical glitches or compatibility issues with the platform you were using in 2022.
Maybe it doesn't fit the tone or theme of your story. Or it could be that adding music might distract from the narrative.
Maybe there's a copyright issue. Some music is protected and can't be used without permission.
Maybe it's due to copyright issues. You need to have the legal right to use the music in your story.