Maybe try holding the phone against the sensor for a minute or so (maybe longer). Don't forget it has to calibrate before it works and allow an hour for that to happen.
Type 2 diabetics are not entitled to the Libre2, or at least that's what I have been told by my clinic. Despite having a thing about pricking my fingers I am not entitled. I have paid £150 for these in the past and they work well, taking away my anguish and keeping me informed of my levels...