can't remove frp via ufs since latest version

Hello

I get this error message with all g930f & g935f that I get

what's the problem please ??

Operation: Reset FRP UFS
Selected model: SM-G935F
Selected port: COM3 USB Serial Port
Software version: 33.5

Hold 'Vol down' and press 'POWER ON' for 2-3 seconds
Checking phone at COM3 OK
Phone detected, do not release 'Vol down'
Reading data from phone... error (2)

Done with Samsung Tool PRO v.33.5