Why do I have SIM error when phone is in a case

[AC Question]

My phone works fine when it's not in a protective case but when it's in my otterbox, I will get a SIM error about a minute after putting it in the case. If I take it out the case for a minute or so, it works fine. I bought a new case thinking it was that but I have the same issue. I cleaned the sim card and used a piece of tape to help hold it tight. How is a case affecting the SIM card?? Can I take the sim card out of my old HTC and try it?