we bought an unlocked moto g play, but returned and have bought a moto g4. we used a sim card in the moto play and it worked fine, but in the new phone it is saying invalid sim card. any ideas why?
Just to clarify: Are you using the SIM card that was previously in the Moto G Play or did you get a new RW SIM card with/for the new phone? If the former then you will need a different, new, SIM card for the new phone. If the latter then try removing Facebook messenger and re-installing it as a recent version of it has been causing the error message you see.
If neither, did the SIM card ever work?
If you deactivated the Play before you activated the G4, instead of simply moving the SIM, then that is the problem. When a 3.0 phone is deactivated the SIM is deactivated and cannot be reactivated.