I've already installed hplip, it printed a test page, but it won't print from any program. It shows the printer in the list of printers, and it's checked as the default printer. I've restarted a couple times.
When I plugged the USB cable for the printer into the computer after installing hplip, it said printer detected. Then after a couple seconds it said the printer was ready for use.
When I send something to the printer, a pop-up shows that a document was sent to the printer - but there's a triangle with an exclamation point in it next to the message. A few seconds another pop-up indicates that the printer has completed printing the job but it didn't print anything.