Part won't stick without a raft

Hi all, I do not seem to be able to get the filament to stick to the platform without using a raft. With a raft, the part prints fine. Without a raft, the extruded filament just "birdnests" at the nozzle because it is not sticking to the platform. My guess is the nozzle is not starting printing close enough to the platform, but again, it works fine when printing a raft. I have cleaned the platform with alcohol and it is quite clean. Thanks,

I figured it out. I needed to re-calibrate the level of the platform. My guess is the nozzle was originally too far away from the platform to get good adhesion. Once I did the leveling (through the on-machine touch screen interface) parts now stick to the platform no problem.

I also re-cleaned the entire platform with rubbing alcohol just to be sure.