There could be several reasons. First, your friend might have set their story privacy to a custom list that doesn't include you. Second, there could be a glitch in the app. Try restarting the Snapchat app. Third, if your friend has blocked you, you won't be able to see their story.
There could be several reasons. Maybe your friend has restricted who can view their story, and you're not on the approved list. Another possibility is a technical glitch in the app. Try restarting the Snapchat app and see if that helps.
Maybe your privacy settings are blocking it. Check if you have restricted who can view your stories or who can send you snaps. Also, it could be a glitch in the app. Try closing and reopening Snapchat.
Check your friend's privacy settings. Maybe they have changed it so that only certain people can see their story. Also, make sure your Snapchat is working properly. Update it if there's an available update. And check your network connection as a bad connection can also cause this issue.