iMessages not downloading from iCloud on macOS

I have several macOS and iOS devices and have sync iMessages in iCloud turned on for all of them. Recently, the mac-mini has stopped downloading messages from iCloud nor syncing blocked numbers or iCloud ids. I have tried disabling/enabling iMessages on the mac, resetting its NVRAM. It won't allow me to toggle the 'Enable Messages in iCloud' value under preferences on the mac-mini and I don't want to disable it for all devices.

I can still send and receive texts on the mac-mini, I just can't downloaded all the synced messages on iCloud. Hitting 'sync now' grays it out for a few seconds but doesn't download any messages.

Anything else I can try?