Hi, does anyone know what happen?

All this time i sent text message without any problem. Out of no where today i sent text message and got an error message saying "your message cannot be sent" then a new message show up saying : Error class: Pernant, Cause Code: Dst.Rs.sht".

Does anyone know how to fix it? so now I cant sent any outgoint message, but able to recieve message.

thanks