What causes network connection failures during a call? July 11, 2023 15:27 Updated This may be due to network congestion.Try calling a different contact or using a different SIM card. Related articles How does a dual SIM work? How often should I shut down and restart Phone (2)? What is the screen parameter of Phone (2)? What causes network connection failures during a call? Can I use other wired chargers to charge Phone (2a)?