LoopMIDI problem

I want to use LoopMIDI in conjunction with e.g. Reaper to play Dorico instruments outside Dorico. When defining a LoopMIDI channel as MIDI instrument very soon after hitting play I get “MIDI error” from LoopMIDI, which switches the channel to silent. Also, before this no output gets to the LoopMIDI channel. I tried this on 2 Windows 10 PC’s and with Dorico 3.5 and 4.2, same results.

When I try the same setup in Musescore 3.6 (i.e. MIDI output to LoopMIDI, LoopMIDI input to e.g. pianoteq) everything is as expected. Much less data are transferred than from Dorico.

Is this a bug in Dorico or am I doing something wrong here?

Edit: I believe I did wrongly define LoopMIDI also as input, so a MIDI feedback loop was created. Sorry for this, you can delete the post.