Every time a user sends a print job, the user must walk over to the...

The message prompting to press "OK" indicates that the printer is waiting for a user input. This suggests that there is some issue with the printer settings, and the most probable cause is that the default paper type has been changed, and the printer needs the user to confirm the paper type before proceeding with the print job. This is a common issue that can occur when the default paper type is not set correctly or has been changed without the user's knowledge.