Nokia 105 4G Sim Card Issues

To make sure it is not caused by something open in the background or similar issue, restart your device by holding the power button, this should refresh the connection.

Try the SIM Card with another device if trouble continues attempt replacing the SIM Card

SIM Card Replacement Guide

Check for any damage to the SIM Card, if so, follow the steps in the guide above to replace it.

Replacement Guide:

Check if connected to the internet, Open the settings app on your device and go into the network settings, check to see if you are connected to your correct network. Ensure your network provider supports VoLTE

Check in your device's settings for any software updates, reserve a full factory reset as a last resort.