Unable to flash TWRP by Odin

Hi, my friend has S6 G920F with stock ROM LMY47X.G920FXXU2BOG8 (5.1.1). I tried to flash TWRP but I was not succesfull.
Steps I did:

• Enabled developer setting, enabled USB debugging


• Turned the phone off, then booted to Download mode


• Installed drivers to Windows 10 (detected as Samsung USB modem)


• Ran Odin 3.10.6 as Administrator


• Select TWRP 2.8.7.1 as AP


• Start flash

I got messages about flashing, everything seems OK, thone was restarted, KNOX is 1 but the recovery isn't there :( When I turn the phone off, then on with volume up + home + power, I got stock recovery (it takes long time to boot there). I tried there my phone and I flashed new bootloader/modem without issues.
Any idea what could prevent flashing TWRP?
Thanks