DIAGNOSIS This points to a power issue, either at the outlet, the cord, or an internal fuse has blown.
FIX First, check the obvious. Is the outlet working? Plug something else you know works into it. Next, check the power cord where it connects to the back of the Opal. It's a removable cord—unplug it from the machine and reseat it firmly. Try a different outlet in another room with a known-good cord if you have one that fits.
IF THAT DIDN'T WORK There's an internal thermal fuse that can blow, often from the machine overheating due to poor ventilation or a faulty component. This is not user-serviceable. If you've confirmed power is getting to the machine and it's still totally dead, it needs professional service.
HEADS UP Don't keep trying different outlets if the machine suddenly died while running. That fuse likely blew for a reason (like a failing pump or motor), and just replacing the fuse without fixing the root cause could be a temporary or unsafe fix.