Begin by ensuring that the SIM card is correctly inserted into the device. Power Off the Device: Turn off your Samsung Galaxy before handling the SIM card. Eject the SIM Tray: Use the SIM ejector tool ...

and press gently until the tray pops out. Most devices just have a single SIM card slot, but some might also have a spot for a MicroSD card and/or another SIM card, so add, remove, or swap any ...