Yes. Restarting the services seem to work but make sure to not just restart dispatcher.
We had the same problem. Infrastructure installed few security updates. But then, over the weekend the services stopped working and hub started throwing the error. Just restarting the dispatched didn't fix the problem. It will work for a minute and then revert back to the error.
I had to stop all Qlik services and start with QRD as stated here - QRD should be the first service to be started/stopped when restoring the central node. Then, it all started working just fine!