You are talking about my example or your file?

If you talk about my example: No, even with 8 hours per day it might be impossible, (for example if you set min 2 hour per day for students)

You always need to think also about students and rooms.

If you talk about your about you file. Please read my post one more time. You forgot to think about morning and afternoon lessons of the students. Your file is impossible that way. You must allow at least one more teacher to work a few hours in the morning. As you can see, even i set a "more difficult" constraint for teacher Halima (I REDUCED the number of allowed time slots), the timetable change from "impossible" to "very easy". You can do the "trick" of course also with other teachers and/or other morning hours if you want. But you can't say that all that so many teachers are allowed to work in the afternoon only, because there are not so many students in the afternoon available, sometimes the students need also hours in the morning.