cellular error

My phone she toff randomly today and the only screen I could see was a black screen with an apple sign and then a screen telling me to connect to iTunes and go to apple.com/support/repair. I did all the steps and it finally came back on but now it is saying my cellular is Error. and its saying it needs to be updated to use cellular. Everything is up to date. I have quadruple checked.

heeelllllppppp