Hey everyone,

​I’m having a frustrating issue with my Galaxy S24 Ultra. It suddenly stopped detecting my SIM card and keeps showing the "No SIM" / "No Service" icon.

​Here is the twist: I tested the exact same SIM card on my old Galaxy S8, and it works perfectly fine there, catches signal immediately, and calls/data work. So the SIM card itself is definitely active and not dead.

​Here is what I’ve already tried on the S24 Ultra:

​Restarted the phone multiple times.

​Toggled Airplane Mode on and off.

​Cleaned the SIM card gold contacts gently.

​Checked the SIM tray and tried putting the card in both SIM 1 and SIM 2 slots (front and back of the tray).

​Checked "SIM Manager" in the settings, but it doesn’t even register that a physical SIM is inserted.

​The SIM card is a few years old, so I'm wondering: could it be a compatibility/voltage issue with the S24 Ultra's modern 5G modem, or is my phone's internal SIM reader fried?

​Has anyone faced something similar on One UI 8.5 / S24 Ultra? Any advice before I take it to a repair center?

​Thanks in advance for the help!

​TL;DR: Galaxy S24 Ultra shows "No SIM". The same SIM works perfectly on a Galaxy S8. Already tried basic troubleshooting (cleaning, rebooting, switching slots) but nothing works.

S24 Ultra not reading SIM card, but it works perfectly on my old S8. Any fixes?