I solved connection & transfer problems on Linux / Chrome by increasing the MIDI I/O buffer sizes from 4k to 64k. The default is apparently too low.
Run the following script as root, after connecting the DT:
#!/bin/bash
dir=/sys/module/snd_seq_midi
if [ -d $dir ]; then
echo 65536 > $dir/parameters/input_buffer_size
echo 65536 > $dir/parameters/output_buffer_size
grep ^ $dir/parameters/*
else
echo Module snd_seq_midi not loaded
fi