The capsule should slide easily into Nima. You should hear a small "click" and feel capsule catch. The top of the capsule should be flush with Nima.
The capsule shouldn't be poking out above the device. If the capsule is not fully inserted, you will receive an error.
Please note Nima will still work even without the click. Just make sure to push the top of the capsule to ensure it's fully inserted in the device. Please contact Nima support if you experience an issue.