This is the second time it said that the button was grayed out. But when I look to see how many minutes or hours that was left it said "slots ready". My basic table said that and I threw it out for another one. That worked until I needed a another crafting table equipment crafting table and now that is doing the same thing. I don't have a lot of money to keep throwing out furniture. Please fix this problem.
The crafting slots are based upon your wizards experience, not on the table you are using to craft... so stop throwing furniture away. There are different types of crafting slots and how many and how often you can craft depends on what you are crafting. That message usually means you have crafted something already and have to wait for the slot(s) to "cool down" before you can craft again.