Please help me. What is wrong in this file?

[Prabhash Paudel]

Please view this file and point out the mistakes there. Out of 785 activities, it can place only 774 activities.

[Liviu Lalescu]

I removed many constraints, and it is still impossible. I attach the reduced file. You probably have a mistake or you want too much from the timetable.

[Prabhash Paudel]

Thank you very much for taking the time to review the file and for your feedback. I appreciate your effort in analyzing the timetable. I will recheck the activities, constraints, and overall timetable structure to identify any possible mistakes or unrealistic requirements. Your assistance is highly valued.

[Liviu Lalescu]

You are welcome! But please see my file, it is easier to check the problem on it, because it has much less constraints and solves faster. I removed all constraints but basic, break, and not available.

[gradgrind]

It looks indeed like something is too highly constrained. BSB/Eng in 12C and 12D can't be placed because the only available slots (because of other constraints) are at times that are impossible for BSB (teaching in other classes). Hope this helps.