Once your phone has been modified, it also proven essential to use the stock firmware if you cannot receive any OTA update anymore Some advanced user have had used the stock firmware if they have messed-up from customization and resulted into bricks, so the stock firmware is also best for fixing unwanted soft-bricks, bootloops or just stuck on a welcome screen logo. Once if all set and ready to fire-up, hit the “START” button in Odin to begin flashing the stock ROM. When the Stock ROM installation successfully completes, you will then see a word “PASS” in Odin. Possible errors that you may encountered, this is based on my own experience while flashing stock ROM on Samsung Android devices.
Once you carefully revert back your phone to NCE stock firmware, try to root again using towelroot.
The stock firmware will be useful just in-case when the time comes that you might want to return back your Samsung Galaxy S5 Active SM-G870 to it’s official firmware. The stock firmware can wipe root or any customization that you may wish to be completely remove from your phone. You can use this procedure again and again, using any future stock ROM that only match with your device.