I had a similar issue with my Samsung Galaxy Tablet before. It turned out the SIM size was off; I was trying to use a nano SIM, but the slot was designed for a micro SIM. It was a bit confusing at first, but once I figured out the right size, it fit perfectly without any gaps. Also, when I was traveling through Europe, I used an eSIM from
Esim Europe, which made things super easy—no swapping physical cards. Just a quick setup and I was connected! If you're still having trouble, double-check the SIM size for your model.