Activate old iPhone without a sim card
I would like to use this old iPhone as an iPod but it is saying "SIM Required." Is there a way for me to activate it so I can just use it as an iPod? I want to use my interval timer apps at the gym. This was working without a SIM until recently. Not sure what happened, but now it's asking for one. I've tried iTunes.
Thank you for any help.
iPhone 5s