Unable to edit Listing!

I’m creating a new listing (my first) and is stuck on the shipping page. I’ve entered all the details for package dimensions, I.e length width etc. and also the unit, but now it’s not letting me save and continue because of these units. When I hover over the fields to update the info or change it, it’s a null cursor and won’t let me do anything. I messaged the help center but I’m not clear on when to expect a response. Does anyone know how to fix this?