Phone must be rooted!
If the software can't root the phone automatically,
then you must root your device manually.
1. Power on the phone.
2. Tap 7 times on 'Build number' in 'Settings'-'About phone' to enable 'Developer options',
go to 'Settings'-'Developer options' and enable 'USB debugging'.
3. Connect the phone to PC with USB cable, install drivers if needed.
4. Select device in ADB settings.
5. Fill values what you need to repair.
6. Press 'Repair' button.
7. Press 'Patch Certificate' if you have network problem after repairing.

Operation: Patch Certificate
Selected model: SM-A260F
Software version: 39.0

Waiting ADB device... OK
Reading phone info...
Model: SM-A260F
Android version: 8.1.0
PDA version: A260FXXU3ASI5
CSC version: A260FOJM3ASI5
Phone version: A260FJVU3ASI1
Product code: SM-A260FZKAXFA
CSC country code: SOUTH AFRICA
CSC sales code: XFA
Phone SN: RZ8M5146C5Y
IMEI: 351584573698741
HW version: MP 0.300
RF cal date: 20190509
Chip name: EXYNOS7870
Modem board: SHANNON315
Security patch: 2019-10-01
Boot Warranty bit: 1
Checking Super user right... true
Initialization zTool... OK
Running zTool, please wait... OK
Reading data from phone... OK
Searching server... OK
Checking server answer... OK
Executing... OK
Searching server... OK
Waiting for server answer... OK
Patching... OK
Rebooting phone... OK

Done with Samsung Tool PRO v.39.0