Why can't I turn on my "Glass Kiln"?

There's a number of possibilities here:

If the kiln isn't attached to your HQ, there's probably a shuttle on the way hauling the Oxygen the kiln needs to operate.

In your screencap, however, I don't see inventory numbers, so it seems your Kiln is connected, but whatever you're using for oxygen generation may not be, in which case you need to wait for shipments to come to your HQ from the oxygen source.

In the second case, you're also out of money. You can borrow money (increase debt) to pay for power and life support, but not industrial feedstock (unless the building is subject to a computer virus). If you sell something you don't need to get some cash, the building should start automatically spending cash to get some oxygen off the market and get started immediately.

That said, it's also possible that you're auto-selling oxygen. If so, turn that off immediately because what happens is that when a shipment of oxygen arrives from the source, you immediately sell ALL OF IT. Then the cashflow problem described above will keep kicking in and locking that kiln up on you.

To review:

1. Make sure you're not auto-selling Oxygen.
2. Make sure shipments are flowing (magnetic storms will ruin your day).
3. Make sure you have spending cash in the short-term.