Loosely speaking I believe this is a generic message and hints at the complexity of the fastboot commands within Android Debug Bridge. Previously you got stuck halfway through the script, now stuck nearer the beginning.
I tried to give an all purpose “long” list of possibilities, I won’t repeat but addressing your response it is always possible that the newest and most expensive PC / laptop might contain a hub unsupported by ADB.
FRP has been seen in a15 due to a google account or a screenlock password or almost anything Google related. In an absolutely unused phone it would not happen but you might check through the threads with this hashtag fp6 where I think there were 3 cases of FRP, might give inspiration.
Edit hashtag created frp