Ollies?

For context, i’ve been skating for awhile now, and i’ve just been focusing on getting around really well, which for the most part has been going well. I’ve been trying to work on getting some air under the board, but for some reason I can’t even push off the board without pushing it out from behind me. As soon as I initiate my jump, the board simply flys out from behind me and I fall. I must be doing something wrong because I can ollie on carpet and grass just fine, but as soon as I get on a smooth surface, splat, i’m on the ground. Anyone have any ideas?