Keurig is a manufacturer of single-serve coffee brewers based in Reading, Massachusetts. Its line of products brew single espresso-style servings of coffee in a few seconds, and contain reservoirs for water and coffee grounds. The water is heated rapidly and forced through a filter containing the grounds, producing a cup of coffee rapidly. Like many such systems and home appliances in general, Keurig brewers can fail to operate, including failing to brew altogether. Fortunately, most problems can be resolved fairly easily.
Check the electrical connection to the brewer. Ensure the plug is securely attached to the outlet. If it is, unplug it and plug in an appliance, such as a clock radio, that you know works. If the appliance doesn't work, your problem is your outlet. Examine the cord carefully for fraying or melting of the insulation or wire. If there is significant damage, the cord will have to be replaced. The cord must be attached to a three-prong outlet directly. Do not use extension cords with two-prong connections, as doing so disconnects the ground wire and can cause your unit to short out.
Determine that the water reservoir has its cap on; this should only be removed to refill the reservoir. Remove the water reservoir bottle and examine its connection to the machine. There is a small filter in that connection that can become corroded or blocked by sediment from the water. Scrub the filter, in place, with a rotary toothbrush and a bit of vinegar. Run a test cup through the machine without grounds to rinse out the vinegar.
Check to see if the descaling signal is on the LED screen. Internal blockage can result from water high in minerals or other foreign matter. To descale, remove the water bottle and empty and refill with vinegar. Turn off the "Auto-Off" function on the control board. Replace the regular "K-cup" with a large mug and press the "Large Mug" button. Empty the mug as it fills. Repeat the "Large Mug" brewing process three times and, leaving the machine running, let it sit for about four hours. Fill the water bottle with water and run it with a large mug in the drip-tray plate. Run "Water Brew" three times or until the water is gone to rinse the machine. If necessary and if the descale signal is still lit, repeat the procedure.
Examine the exit needle, which feeds the coffee to the K-cup. This can be blocked or partially blocked with coffee grounds, leading to partial fills or no flow. Lift the top of the K-cup holder at the top of the machine and remove the entire assembly by lifting from the top and pushing from below. The exit needle will be left in the reservoir. Reach underneath the reservoir and push a toothpick or straightened paper clip up through the exit needle from below. If grounds emerge, continue probing, then rinse with a bit of water. Probe again, and repeat if necessary. Allow to dry completely before reassembling. There are sharp parts here; be careful when handling the exit needle.