First thing to check when your printer wont print is the job status. Open your printers folder and choose the printer in question. (Press the windows key, or click on the Start menu. Type in "Printer" and choose "Printers and Scanners". Click on the printer in question and choose "Open Queue". Check and see if your document is there and stuck. If there are many documents in the queue, you will want to cancel them all and retry. Sometimes one gets stuck holding all the others up.
Secondly, if the printer is not printing check and make sure the printer itself is still connecting to your computer. If it is wireless, make sure the wifi light is on solid and not blinking. If blinking, reset up the wireless connection. A brief google search using your printers model and the words "wifi setup" will net you instructions on how to set up the wifi again. Otherwise check the printer cable and make sure nothing has come loose from the printer or the computer.
Lastly, try restarting your computer and the printer, then see if the item in question will print.
If all else fails create a support ticket and include what steps you have already taken.