Miele CVA615 Espresso/Coffee Machine - Steamer stopped working?

Hello, I have a Miele CVA615 that won't dispel steam. When I turn it on nothing comes out and eventually "expel air" message (if I attempt to turn the steam on a few times). The hot water dispenser works fine. I have thoroughly cleaned and checked the steamer sleeve and valve and neither are blocked. I get no water from the steamer, only from the hot water dispenser (works fine). The steamer recently began lowering it's steam output and now, nothing comes out. I have not disassembled the steam heater and/or H2O lines yet, as I am a little worried about getting deeper than my skill sets today, as I am not a Miele repairman. Considering the price and risk of ruining anything, I was hoping to get some better educated advice from a technician before I go deeper into the unit to explore possibilities.
Any help is greatly appreciated!!