Push notification gateway non-functional

I’m using a self hosted instance using docker, and I registered it to a cloud account. It’s on an enterprise trial, with registered mobile devices, but no notifications are being sent. The UI shows a success message when I send a test notification and acknowledges one device, but doesn’t send it at all. Any ideas? I tried removing the workspace from the cloud account but it fails saying it couldn’t remove it.

Any ideas? It’s being quite weird.