1. In the kernel selection screen when system booting, press the arrow keys(↑,↓) to select kernel and press "e" key to go GRUB.
2. Input " rd.break" at the end of the line containing "linux16" and press "ctrl + x".
3. # mount -o rw,remount /sysroot
4. # chroot /sysroot
5. # passwd
6. # touch /.autorelabel
7. Press ctrl+d
8. Press ctrl+d