Unauthorized system

[Ilanpalatn]

I've got a Samsung galaxy s4 active form at&t and rooted it. Some days ago, at&t requested an atualization on the system and performet it. After that, when the phone is turned on, it shows a message saying that an unauthorized system software has been found and it says secure fail: kernel. I tryied uploading another operational system but I found out that at&t added a lock that doesn't allow you to change the operarional system. Is there anyway to fix it?

 

[UJ95x]

I've got a Samsung galaxy s4 active form at&t and rooted it. Some days ago, at&t requested an atualization on the system and performet it. After that, when the phone is turned on, it shows a message saying that an unauthorized system software has been found and it says secure fail: kernel. I tryied uploading another operational system but I found out that at&t added a lock that doesn't allow you to change the operarional system. Is there anyway to fix it?

Welcome to Android Central
That sounds like the Knox security warning. It was added to all Galaxy S3/4/4A and Note 2s on Android 4.3 or later.
It will not let you install any other ROMs and blocks again firmware downgrades, so unfortunately there is no solution at the moment

Sent from my Galaxy S4 running SlimKat 4.4.2