DIAGNOSIS The brewer is in its mandatory first-use setup mode. It won't brew until the internal lines are filled with water.
FIX Run a water-only brew cycle without a pod. Fill the reservoir to at least the minimum line with cold water. Place a large mug on the drip tray. Press and hold the 8oz and 10oz brew buttons simultaneously for 3 seconds. The screen will say 'PRIMING' and it will run a long cycle. Let it finish completely.
IF THAT DIDN'T WORK If it still shows 'PRIME LINE' after that cycle, the initial prime may have been interrupted. Unplug the brewer for 60 seconds, plug it back in, and repeat the simultaneous button press prime procedure.
HEADS UP The first few water-only cycles may sputter or produce small amounts of water—this is normal as it clears air from the system. Don't try to brew a pod until you get a full, steady stream of water.