Sim not working
sim saying invalid
iPhone 5, iOS 8.4
sim saying invalid
iPhone 5, iOS 8.4
You need to talk to your carrier about getting a new SIM card. Some more information may help us to give you some other solutions.
If I had to guess, I'd say you have a phone that's locked to a carrier other than the one you're trying to use, but without some actual information, that's just a WAG.
Sim not working