This could be related to your cellular signal or WiFi connection. Check to ensure you have a strong data signal (3+ bars with LTE), or ensure your WiFi signal is strong. If you've confirmed your connections are strong and you don't have any other problems accessing the internet from your phone, try signing out of your account and signing back in.
We've noticed that in some cases, iOS updates (both automatic and manual updates) can end a 10-21 Police Phone session without logging out of the account, resulting in the same error: "No Internet Connection."
If you continue to have issues even after signing out and signing back in, email
10-21.support@motorolasolutions.com for support.