Most devices of Samsung Galaxy series, require ‘File Transfer’ connection mode after connecting USB cable, before starting FRep2 Precision mode setup tool on PC/Mac, to keep StrServ process after cable disconnection.
However, some device models (maybe after some system update) fail to keep StrServ process even with ‘File Transfer’ or other connection modes. From user’s report, installing Samsung DeX to PC fixes the issue, to keep StrServ process after the setup and USB disconnection.