No Sim Card = Daily Occurrence (after I encrypted phone)

3-4 days ago, I encrypted my Sprint Note 4. Since then, I've had "No Sim Card" errors once or twice a day, usually following the receipt of a text message from 8737 with a bunch of gibberish. A reboot fixes the issue, but it's starting to get a little annoying. A quick google search hasn't turned anything up (hence the post).

I'm running 5.1.1, I'm not rooted or anything like that. Suggestions would be greatly appreciated.