max operational Frequency

If you don't set a timing requirement then success / failure won't be reported. You should still what that timing is though (e.g. if you haven't set fmax then you won't get a message saying that fmax hasn't been read but if you look in the report it should still tell you what it is).

What have you set tpd to? How close to meeting it are you?

If you only narrowly miss the tpd requirement then you might be able to add some placement constraints to help the fitter (you'll need to read up on that). If you're quite a way off then you'll probably have to change your design.