I'm trying to use a Twilio Sim card in an (Alcatel One Touch) TracFone. I'm getting a message saying "Sim Not Valid" when I turn the phone on with the Twilio Sim card inserted. I'm wondering if this is an issue where the phone needs to be jailbroken first? Or whether it's some other issue.
Twilio developer evangelist here.
From what I can tell, TracFone is an MVNO (virtual mobile carrier). If you have bought a phone from them, it is likely locked to their network which is why it deems that the Twilio Sim is invalid.
You don't need to jailbreak the phone (normally meaning to hack the operating system to allow for sideloading applications) but you will need to get in unlocked. You can normally call up your carrier to do this or use a third party service to do so.