MIDI keyboard don't connect

Hi all !
I'm using Musescore 3.4.2 in Ubuntu 18.04.04 and a MIDI keyboard AKAI LPK25 and i can't enter anything with it.
1- The keyboard itself is OK: aseqdump logs effectively events.
2- Musescore don't show in aconnect -i (when running, of course) as it did in older version.
3- Using Alsa option in I/O settings disable the MIDI input button. Using PulseAudio instead enable the MIDI input button, but this don't work.
4- Starting Musescore in terminal show some errors but mainly:

ALSA lib conf.c:3916:(snd_config_update_r) Cannot access file /usr/share/alsa/alsa.conf
ALSA lib pcm.c:2495:(snd_pcm_open_noupdate) Unknown PCM default

Which is strange because the file exists and has read access to everyone.

Any idea to fix the problem ?
Thanks in advance