recording with backing track and microphone, using Rode AI-1

Hi there, I am new to using audacity and I have a problem recording my Saxophone (with a microphone) and combining this recording with a backing track.
My windows version is windows 10 home, the audacity version I am using is 2.3.3

Initially I have loaded the backing track and as an output I have selected the loudspeakers from my computer. That all works. However I do want to use my headphone to listen to the backing track en record my Saxophone without the sound of the speakers in the room.

I have plugged my headphone into a Rode AI-1, changes the setting in Audacity to ‘line (Rode AI-1) but then the recording won’t start when I push the record button.
Just nothing happens. When I do not upload a backing track it does start recording with these settings. So, I don’t understand what is wrong in the settings and I am following the setup as I see it in the manual. So, hopefully anybody who knows what I am doing wrong here?

Thx in advance

Unplug the headphones and turn down the monitor headphone volume.

Do you have the USB light (far right).

Turn the microphone volume all the way up. Speak to or scratch the microphone. Do you get the tiny green “squiggly line” light flashing?

Does your microphone require Phantom Power (+48)? What is the microphone?

Koz