Howdy Simpson, thank you for asking us your question about the Samsung Galaxy S25 Ultra. To resolve what you've described to be experiencing with your Wi-Fi calling feature, please restart your device, then reset network settings, ensure your Wi-Fi is stable, update your phone's software and carrier settings, and verify with your carrier that your line is provisioned for Wi-Fi calling. If you have any other questions or if you would like any further assistance, please feel free to contact Support at your earliest convenience. Thank you for choosing Samsung! - Debra