Hi, first can I confirm the settings you are using inside DT?
In settings > sync:
is clock receive, prog change receive both checked?
In Port config:
have you tried with both turbo speed disabled / enabled?
is input set to midi+usb or usb?
is receive notes box checked for yes?
is receive cc/nrpn box checked for yes?
is param output set as cc? (is ableton receiving cc or nrpn when you are pressing the record and holding on digitakt before pressing play in ableton?)
in channels menu:
if program change IN CH is set to auto, have you tried to set a specific channel and match it to the channel you’ve set it up with in ableton?
PROGRAM CHG IN CH selects the MIDI channel that will listen for incoming program change messages. An AUTO setting will use the AUTO channel, I believe auto channel is by default set to 10? Digitakt should be already config to respond to program change messages from the MIDI SYNC menu.
in the system portion of the settings menu, under usb configuration is this set for usb or is it set for usb audio/midi? maybe have you tried both to see if it makes a difference?
if these things are all set try using cc 20 shown on the midi appendix of (I think pg 83?) DT user manual. You can also reference the midi cc value guide there if it is more helpful.
Not sure if I have any other good info sorry.
Are you doing this in live recording mode or grid recording mode of the digitakt?