@gem12345: Before you proceed with the steps below, we recommend reaching out to your network provider to enquire about any restrictions on your account, or any known problems with the service in your area. To do so, please connect to Wi-Fi, and head to your provider's website via a browser app (Samsung Internet or Chrome) where you will be able to utilise online contact options, such as web chat.
To troubleshoot the issue please open the Phone app > Tap the 3 dots in the top right > Settings > Supplementary Services > Call Barring > Voice Call, and make sure that all options here are toggled off, especially 'All Incoming Calls' and 'All Outgoing Calls'. Now, close the Phone app and head to Settings > Connections > Flight Mode, and toggle this off if it is enabled.
If the issue persists, please power off your phone, remove your SIM, give the gold contacts a rub, and put it back and power back on to see if this helps. To further troubleshoot the issue, please head to Settings > Connections > SIM card manager, and make sure that your SIM is recognised, and toggled on. Also, you may wish to head to Settings > General management > Reset > Reset network settings > Reset settings, although please be aware that this will also reset your Wi-Fi and Bluetooth settings. Please can you also try your SIM card in another compatible phone, as this will help to determine if the problem lies with the phone, or your SIM/network provider.
