help on error - preferred rooms constraint

[liquid]

I'd ask for explanation of this error which I don't understand:

Cannot generate timetable, because for activity with id==312 you have no allowed preferred room (from preferred room(s) constraints).

[Volker Dirr]

I guess there are at 2 or more conflicting room constraints referring to the same activity.
For example a room constraint for subjects and and other room constraints for activity tags. FET try to care about both but it is impossible in your sample.

Go to FET -> Data -> Activities and select activity id 312.
Check the information about at the right side (if you use a left to right language). You can see the room constraints there. Maybe you already understand then why it is impossible.

please attach your file if you can't find the problem.

[liquid]

I've solved this. I haven't added the room for subject allowed rooms. Thanks.