I think I know what the problem is. I assume you have speakers hooked up to your DM.
If so, then you will have to assign two channels from the Mac (not Logic) to two channels on the DM, and make sure these go to the Stereo Out.
See the screens. Sorry they are in Dutch, but you can figure it out, I'm sure. Go to
Audio Midi Configuration and make sure the audio devices window is open. Then select the FW card in the list on the left. In the right hand panel you will see figure 1. Click on Configure speakers. This will open a sub windows (figure 2). Select which channel you want to use to send the normal stereo sound from your Mac to the DM. For channels 1-16 select stream 1. For 17 to 32 select stream 2.
Then select a channel for each speaker. 1 and 2 would be logical, but nothing prevents you from selecting 31 and 32 for example. Or 9 and 13.
Check to see if iTunes or Spotify (or any other program with sound) is sending a signal to the desk. Assuming you have routed FW channel 1 to channel 1 on the desk and so on, you would see the corresponding meters show the signal. This is essential by the way, to check any incoming signal on the desk. This means the connections are good, and if no sound, then we would have to look at the internal routing on the desk. But first we need to make sure that the routing from the Mac to the DM is setup correctly.
If this works, then it should be OK. Because the stereo out from Logic by default goes to the same stereo out as any program on the Mac.
Once this setup works, you can look at the rest of the channels to/from Logic <-> DM.
NOTE: I see you don't have the mkII version of the FW card. This should be visible in Logic as IF/FW-DM mkII instead of IFFWDM(0075). I don't know whether this card still works on later macOS.
And EDIT: I think the DM 3200 only accepts 16 of the FW channels, not sure. I'm using a DM4800. But the steps in principle are the same.
