You can - but if you have the time, I would let the ribs defrost. Frozen ribs will take a lot longer to cook, and the seasoning won't penetrate the ribs as much. If you absolutely have to, give yourself a lot of time and don’t rush it - if the temperature is too high, you will just end up with tough meat, so the ribs still have to be cooked low and slow. If you are in a rush and your meat is frozen, I would cook the ribs in an Instant Pot instead and sear the outside of the ribs to lock in more flavor.