how do i reset my phone (samsung j2 prime)

[AC Question]

please, help me, my phone is always restart and stuck in the logo, i have doing anything like factory reset, clear the cache but it doesn't work and the phone has a word with yellow color 'kernel warranty : 0'. what i must to do? please help me.

 

[BrutalhonestyM]

Knox has probably detected modified files on your phone at boot up and now the warranty is void. Have you rooted your phone or you might have done it by accident. If so you need to do a back up of all your files and unroot your phone.