The reason could be that your account settings are preventing it. Sometimes, there are certain privacy or content restrictions in place. Also, make sure the song is compatible with the IG story format.
Sometimes, it might be because of a glitch in the Instagram system. Wait for a while and see if the issue resolves itself. Also, check if you have enough storage space on your device for the upload.
Maybe there's a glitch in the app. Try restarting your device or reinstalling the Instagram app.
It could be that your device doesn't have the latest version of the Instagram app. Check for updates and install if needed. Also, make sure you haven't reached any limits on adding stories set by Instagram.
It could be that your IG version isn't updated. Make sure you have the latest version to access all the features, including adding music to your story.
It might be due to a network issue. A poor internet connection can stop the music from being added. Try switching to a different Wi - Fi network or using your mobile data instead.
Maybe there's a glitch in the app. Try restarting your device or reinstalling the Instagram app.
It could be that your internet connection is unstable. Check your Wi-Fi or data connection. Also, make sure you have the latest version of IG installed.
It could be that your IG account settings are not allowing it. Check your privacy and media settings to make sure music is enabled for your stories. Also, make sure you have the latest version of the app installed.
It could be that your IG version is outdated. Make sure you have the latest update installed. Also, check if your music library is properly synced with IG.
It could be that your IG version is outdated. Make sure you have the latest update installed. Also, check if your account settings allow for music integration in stories.