Lactic Threshold detection help

I've tried and failed twice now to do the guided lactic threshold test. I hit my lactic in the low 160s yet when this step completes the watch asks me to run 3 mins at 170 - 180 bpm and 3 mins at 180 - 190 bpm, neither of which I can as I've hit the wall! It then follows up with lactic not detected.
Any tips to solve this issue? I also have lactic auto detect set up and it is yet to auto detect.
Max HR: 189 which has been auto detected and zones are set up correctly
Watch: Forerunner 265
HRM: Polar H10