Check you internet connection on the device, try accessing Instagram from a different device and check if you see the same problem. If neither work, report a problem to them and you should hear back from their support. Here's Instagrams directions on reporting an issue.
"How do I report a technical problem on Instagram?
If you think you've found a technical problem on Instagram, you can report it from within the app. To report something that's not working:
1.Go to your profile by tapping
2.Tap in the top right, and then scroll down and tap Report a Problem
3.Tap Something Isn't Working and explain the problem you're seeing
Make sure to include as much detail about the problem as possible in your report. Information like the kind of phone or tablet you were using and what you were doing when the problem occurred may help us to address the issue. "