Made a few reservations using the DB Navigation app on my phone for a trip coming up later this month. Reserved first class but no seat reservation was available and I dont see how you can. Later I realized I probably needed to go into something called fleet. How was I able to reserve tickets in first class yet I am not guaranteed a seat?
Info: on regional trains you cannot reserve seats. Was it a RE or RB connection?
More info about seat reservations on long-distance services.