Unlocking using sever:
1. Power on the phone.
2. Tap 7 times on 'Build number' in 'Settings'-'About phone'-'Software information'
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. Press 'Unlock TMB via server' button, write your login and password in window if it will appear.
(Login and password will be saved as default after first input and can be changed in settings.)
Operation: Unlock TMB via Server Mar 2020
Selected model: SM-J260T1
Software version: 43.19
Checking Login and Password... OK
Balance: 24 crd.
You have 24 credit(s) left. This operation takes 5 credits. Continue? Yes
Waiting ADB device... OK
Reading phone info...
Android version: 8.1.0
PDA version: J260T1UVS7ATJ1
CSC version: J260T1TMK7ATJ1
Phone version: J260T1UVS7ATJ1
Product code: SM4J260TZKATMK
CSC country code: USA
CSC sales code: TMK
Carrier ID: TMK
Phone SN: RF8MB2ABMRH
HW version: REV1.0
RF cal date: 20191121
Chip name: EXYNOS7570
Modem board: SHANNON305
Security patch: 2020-10-01
Boot Warranty bit: 0
SIM State: ABSENT
Initialization zTool... OK
Running zTool, please wait... OK
Reading data from phone... error (0 5.2)
Reboot phone and try again.
Check ADB drivers, USB cable. Don't use USB Hubs
If this repeated then reflash phone and make factory reset.
Done with Samsung Tool PRO v.43.19