APN not saving with unlocked sprint Note 5?

I've had this issue before with another Sprint phone. Its unlocked and I'm trying to use it with Verizon. It gets service but only roaming service. And then when I set the apn settings, it just doesn't save. Hit save and it's just not there. Tried reset, wifi on/off, restart, etc. I've found that it's only once I try to edit the MCC or MNC that it's messes up. Please help!