Has anyone had any luck with faraday bags? I bought one a few years ago, which worked fine for my galaxy s6. I tried it not long ago with my galaxy s9, and I

Has anyone had any luck with faraday bags? I bought one a few years ago, which worked fine for my galaxy s6. I tried it not long ago with my galaxy s9, and I was able to call it from my land line even though it was covered by the faraday bag. Maybe changes in frequencies are to blame? Or maybe I didn't have it as sealed in as well as I thought.