Put your rollers as far apart as they can be - even if your media is smaller. Do a load at current position. Then open the clamp, move the wheels closer to your media and click continue.
Move the head as far in the corner as you can , past the black box on the top and the side, and set that as your home position.
Then jognover to the mark and hit barcode.
If it acts like it doesn't even try by beeping once, usually that means it's detecting your barcode is past the home position - either because you printed it too close to the edge and it can't read it (common with a 54" cutter and 54" material) or because when you loaded it, it set your home too far away.
If that works... You can expand your cut area, it helps a bit but not much. The better solution is to add some offset in onyx.