System don't start

Question

Ita a 2019 GMC Sierra, I wanted to add a 942 extender, I already did all the process on key decrypt, and when I try to start it display on vehicle says key is not in the vehicle and don't start, but if I try to start it up and get the key inside it will start, I did master reset and key relearn procedure and keep doing same thing

Answer 1

Is this with t-harness or wire-to-wire?

Please try the reset again, "release on red then press and hold".