Few things you can do first:
1. Check your KYC status pn 'your account' menu. In order for your order to be processed, you would first need to complete your KYC process.
2. Check your Nanovest history and see if the order has been placed successfully
3. Close and re-open Nanovest app
If you have done the steps above and it's not working, please reach us at care@nanovest.