This is the first time I cannot generate the time table
You deleted the 2 basic constraints that are always needed.
Please go to FET -> Data -> Time constraints -> Miscellaneous -> Basci compulsory time constraints
Press "add" and "add constraint"
After that you will get a new warning, since you also deleted the basic space constraint.
Please go to FET -> Data -> Space constraints -> Miscellaneous -> Basci compulsory space constraints
Press "add" and "add constraint"
After that you will see tha FET still can't generate the table because of problem in year 11.
Please check if the activities and students structe is fine.
If they are fine it sadly looks like you need to delete the students not available times in year 11.
it looks like all groups can have free 2 hours, but not all at the same time.
so maybe it is better to replace that constraints by a max gaps for students=0%.
So they will get free at a random day in the first or last hours.
you can improve it maybe a bit more by adding an early constraint and also a min hours per day constraint.
it might be possible to sove this bug also by swapping teachers in the activities. i didn't checked that yet. i guess you will see it faster than me if you generat a (timetable without that constraints) and check the (maybe not finished) results.