Prompt [Q] how can i fix my phone i337

I rooted my phone, but it still appear secure write enable when i tried to use ODIN. I was able to put recovery and flash customs roms, but when i tried flash one, I make the wipe data,cache and dalvik and after that i my phone doesn't start, and on the recovery bootloader appear the message "secure fail :kernel" and System software not authorized by AT&T has been found on your phone. Please can someone help me !!