I have a different model, but the water reservoir is in the same location. After four years of no problems, the water output kept diminishing until it totally stopped. I searched for a remedy, but found none that worked.
You may consider this a little inconvenient, but it works perfectly for my Keurig.
When starting the process, remove the top of the water reservoir. After pressing the flashing blue light, the sound from the unit changes after about 2 or 3 seconds and when this happens, hold the tip of a finger over the nylon drain tube until the brew cycle ends. For some unknown reason, the air flow is expelled through this outlet, instead of forcing the hot water to make the coffee. Blocking the air forces the internal pressure to expel the hot water as it was intended to do. As long as this works, I will delay purchasing another unit.
Chuck Dimmitt