Hello everyone. Very sorry you’re running into this.
Is this happening on normal rolling deploys, where there are no stopped Machines?
If you are cloning a machine with a volume, increasing the RAM or CPU specs on your Machines, or using canary or blue-green deployment, [I was wrong about this; canary and blue-green should actually have helped if you don’t have volumes, because they replace Machines with new ones that would land on a host with capacity, rather than updating in place] you may run into this if you happen to be on a near-capacity host. This can also happen if your Machines have auto-stopped and the host doesn’t have enough CPU or memory free to start them up again when you deploy.
In that case the best solution I know, unfortunately (for the moment) is to create a new Machine (and volume, if needed), which should land on a different host in the same region.
But if you’re deploying only to update the image, and your Machines are already running, you should not hit any resource errors. Please let us know if this is the case!