Go to: More > Settings > Contacts to Display. Your settings should be set to All contacts or use Customized list and turn on all the options to enable more contacts to be visible from within the app.
What happens if I deny app permissions?
Some things won't work Once installed, it requests access to your camera. If you click Cancel the app cannot use the camera, so you won't be able to share your own snaps. The rest of the app should continue to work though so you will be able to receive messages, and to view other users' stories.