If you're having trouble enabling your camera on Instagram, there are a few things you can try. First, make sure that your phone's camera is working properly. If it is, then check to see if the Instagram app has permission to access your camera. To do this, go to your phone's settings and find the Instagram section. Underneath the app's listing, there should be a toggle for Camera. Make sure this is turned on.
If neither of these solutions work, then it's possible that there's a problem with the Instagram app itself. Try uninstalling and reinstalling the app to see if that fixes the issue. If not, you may need to contact Instagram's customer support for further assistance.