Mac Mini - Logic Pro X Recording HELP!

I have brought a Mac Mini for around £600 along with Logic Pro X. Logic works great! But I need a midi keyboard that works with it on a mac mini! I was thinking that any midi keyboard could be compatible with this Mac, although when I brought my M Audio Keystation 49 it was barely even turning on not even letting me play the keys or anything! I called up an expert and he said M Audio do not do anything compatible with a Mac Mini (something to do with their new USB ports or something). So I need help! What will work with my Mac Mini on Logic Pro X??!