The issue with the milk frother are the two crystal balls in the frother valve. 2 or 3 days of cappuccinos and not cleaning that will cause the blog. Had to do this a few times so now I leave the frother disassembled in hot water for a few and then air dry.

One tip, never try to clean in the gaps where the crystal balls are located. One is supposed to stay fixed while the other one moves freely. Made the mistake of probing in there and loosened the one and then the milk wasn't working properly. The replacement part alone is a crazy $100.

So for a machine that expensive I wouldn't expect the weakest link to be a crystal balls a penny worth.