Root.
If you have encountered this message, you are likely stuck in a limbo between a stock device and a rooted one. This error typically appears when a root management application, a custom modification script, or a piece of software tries to access the su (superuser) binary, but finds it missing, improperly linked, or unresponsive. root not available install supersu and perform root first
Manually check (via TWRP file manager) that /system/xbin/su exists and has -rwxr-xr-x (0755) permissions. Also check /system/bin/su . Manually check (via TWRP file manager) that /system/xbin/su
Essentially, you have the remote control (the app), but the TV (the actual root access) isn't turned on. Why is This Happening? Why is This Happening
Open SuperSU. It will prompt to update the SU binary if needed. Choose (for standard root) or TWRP/CWM (if normal fails). Reboot.
Android 5.1+ introduced dm-verity (detects system partition modifications). Flash a “no-verity-opt-encrypt” ZIP after SuperSU.
Here is the definitive method to eliminate the "root not available" error.