Hetzner us-east, now you can get only the smallest instance (CPX11)
status.hetzner.com
status.hetzner.com
Our solutions (from simplest to the most sophisticated).
Use a different datacenter, for instance instead of Falkenstein, use Helsinki.
If that does not work, then instead of using web GUI, use either terraform or hcloud in console. Usually what was shaded in the GUI, worked through console.
If that does not work, try to loop terraform or hcloud in the console with a 5 minutes sleep time in between retries (mind hetzner api rate limit). Usually we could get up to four machines overnight. What we discovered (might not be true any more) is usually around 4-5AM european time, some machine types were going back to the pool.
But the real problem is IMHO the pricing change Hetzner release around 6 months back. This is my guessing here, so do not hold me accountable. All those cheap servers are now called 'Cost Optimized' and are mostly not available. The new group is called 'Regular Performance' - they are twice that expensive as 'Cost Optimized'. Also, notice that Hetzner has around 2 months ago released an official email to all customers that they have to raise their pricing, claiming they cannot keep up with the cost of labour/hardware to keep it running.
If you try to connect the dots, it looks like they just want to force people to move to the 'Regular Performance' group (2x cost) over time, to balance out the earnings.
To comment directly on your 'cpx11' problem. This is 'Regular Performance' group, so you are already in Hetzner's 'target'. I believe if you use one of the techniques I gave you above, you should be able to acquire that machine.