Unhappy [Q] help Samsung galaxy s4 i337 semi bricked

okay so i had my Samsung galaxy s4 i337 4.4.2 running fine with root and superuser installed but i tried to install a custom recovery specifically im un able to link it at this time
i did this using recovery tools now i'm getting a message when my phone starts up with a big exclamation mark saying software not authorized by at&t has been found on your phone is there any way to fix this please help me i don't care if i loose root access or anything i just need/ want my phone to work again