You might see CUPS periodically, maybe a few hours or days, changing printer status to “Paused”. Please see below picture for how it would look like on CUPS admin page. Once the printer gets paused, it will not process any print jobs. You have to do ‘Resume printer/accept jobs’ in cups admin page to get the printer working again.
There are many reason for this behaviour like filling up the CUPS cache, a problem the spooling, etc., You may add below lines in system startup to clean CUPS cache and spool everytime when system start.
service cups stop
rm -r /var/cache/cups/*
rm -r /var/spool/cups/*
service cups start