1. Ensure your provider’s service is active on your phone.
2. Confirm that you have signal bars if it's a cellular phone.
3. Restart your phone and wait for it to fully boot, and then try making a call. If your phone can make and receive calls, the issue is solved.
4. If you are unable to make a call, go to your provider’s website or contact your provider’s customer service line to confirm your account is in good standing.
5. If the account is not in good standing, resolve the payment issue before trying to make a call again.
6. If your account is in good standing, contact your provider to ask for help troubleshooting the phone.