Tmobile worked on Verizon S8+ for a day then stopped. Help?

[AC Question]

Just bought a used S8+ on Craigslist. Everything worked fine, it's unlocked, it has all APN's available in the settings for other providers. It worked for a day, but an hour ago stopped working. Checked to see if IMEI is clean, it is. Tried other sim cards from t-mobile, no change. Tried the sim card back in my old phone (HTC M9) and it works just fine. On notifications is it saying "SIM card is not from Verizon Wireless". Thats it, no other error messages.

I'm really lost, don't know what to look for or what else to check, any help would be greatly appreciated.

 

[HaloGirl22]

Look for the carrier settings and try to switch it to your current carrier.

 

[aokusman1]

Call t-mobile and have them check the imei. Looks blacklisted to me.