As cliche as it is, from time to time it makes sense to restart your mac. They usually work great and can go for months without a restart. But then that day comes and something unexplainable happens. Than it is time to restart.
Something clearly changed, so just uninstall then reinstall the printer on the Mac.
I have a MAC running OS10.12.3. Out of the blue, my printer stopped recognizing my computer. I send a document to print, the computer shows the printer going from "Idle" to "In Use". But the printer remains at "Ready" and doesn't print. I have changed nothing since the last time I printed. Help!