The sim card tray is self popping out @KF1980 ?
Look inside with a torch to see if any debris is in there.
Ensure they are both seated correctly and as a process of elimination try just using the sim card leaving the sd card out and then see what happens.
If not seek support from a Samsung Experience Store or Samsung Service Centre.
🌈 Stay Safe & Stay Alert. 🌈
Current Phone > Samsung Z Fold³ 5G.