Can't register new keys

[nlt999]

Hi!
2007 Lexus RX350 - Trying to register new keys using techstream. Everything goes normally until the actual registration step.. says it is registering and timer starts the countdown, then after several seconds it stops with message:
"Key Registration has failed. The communication error occurred between the key and the ECU".

DTCs logged are B2794: Unmatched Encryption Code B2795: Unmatched key Code B2798: Communication Malfunction No.2

Tried it using two new keys.... same failure message.

I WAS able to successfully program the remote-entry buttons on those same two keys using the Techstream.


Anyone have any knowledge/ideas about this please??
Thank you! Nick