If your DT is successfully sending midi to other devices, I have to assume that your system settings are fine. After that, all you need to do is match your midi track channel to the Pro-1 and it should be receiving. There really isn’t anything tricky since the P1’s midi implementation is so basic. This makes me think that you have an issue with the Pro-1 rather than your DT’s setup.
The last thing I can think to check: Is your midi-track muted (check both purple and green)? I may or may not have had a wtf meltdown at one point in the past trying to figure out why a track wouldn’t play, and it was globally muted track that I hadn’t noticed
They’ll suggest confirming you have checked that your MIDI note is high enough - the MIDI input range is bounded and set high compared to some - remember the synth has its osc frequency ‘footage’ settable on the device
Be sure your DT is outputting MIDI on DIN by using another device and if possible something other than DN as input too - basic checks
Check your MIDI cable too
My hunch is that you’re in too low a ‘register’ in terms of MIDI notes
Have you updated the Pro 1 to the latest SW version? Also I remember some of the B synths were a bit funny regarding the pulse width/duration of incoming midi notes. If the note length was too long then the instrument didn’t trigger. I thought I’d read this had been sorted out in a SW update but I could be wrong. Try shortening the note length on the DT and see if that helps