nlogit - level 2 alternative variable alt not found

[Joo Young Kim]

Dear scholars,

I am having a problem running nlogit after the specification of nlogittree.
I have three choice types (1, 2, 3) and the message that I got when I ran nlogit was "level 2 alternative variable alt not found."
I have tried to find out by myself but could not get improved yet as I'm not familiar with the nlogit model...

So it would be very appreciated if I can get any advice.

Thanks,
Jooyoung