Jack can't open ALSA sequencer as a client

[fredmyra]

I am getting the following message when starting QJackControl:

22:16:23.248 Statistics reset.
22:16:23.258 Could not open ALSA sequencer as a client. ALSA MIDI patchbay will be not available.
ALSA lib seq_hw.c:466:(snd_seq_hw_open) open /dev/snd/seq failed: Åtkomst nekas
Cannot connect to server socket err = Filen eller katalogen finns inte
Cannot connect to server request channel
jack server is not running or cannot be started
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock

If I then try to start QSynth the message becomes:

22:16:23.248 Statistics reset.
22:16:23.258 Could not open ALSA sequencer as a client. ALSA MIDI patchbay will be not available.
ALSA lib seq_hw.c:466:(snd_seq_hw_open) open /dev/snd/seq failed: Åtkomst nekas
Cannot connect to server socket err = Filen eller katalogen finns inte
Cannot connect to server request channel
jack server is not running or cannot be started
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
22:19:01.138 JACK is starting...
22:19:01.138 /usr/bin/jackd -r -dalsa -dhw:0 -r44100 -p256 -n2 -Xseq
Cannot connect to server socket err = Filen eller katalogen finns inte
Cannot connect to server request channel
jack server is not running or cannot be started
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
Cannot create RT messagebuffer thread: Operation not permitted (1)
Retrying messagebuffer thread without RT scheduling
Messagebuffer not realtime; consider enabling RT scheduling for user
no message buffer overruns
Cannot create RT messagebuffer thread: Operation not permitted (1)
Retrying messagebuffer thread without RT scheduling
Messagebuffer not realtime; consider enabling RT scheduling for user
no message buffer overruns
Cannot create RT messagebuffer thread: Operation not permitted (1)
Retrying messagebuffer thread without RT scheduling
Messagebuffer not realtime; consider enabling RT scheduling for user
no message buffer overruns
jackdmp 1.9.17
Copyright 2001-2005 Paul Davis and others.
Copyright 2004-2016 Grame.
Copyright 2016-2021 Filipe Coelho.
jackdmp comes with ABSOLUTELY NO WARRANTY
This is free software, and you are welcome to redistribute it
under certain conditions; see the file COPYING for details
JACK server starting in non-realtime mode
self-connect-mode is "Don't restrict self connect requests"
Cannot lock down 107341338 byte memory area (Cannot allocate memory)
22:19:01.215 JACK was started with PID=30766.
audio_reservation_init
Acquire audio card Audio0
creating alsa driver ... hw:0|hw:0|256|2|44100|0|0|nomon|swmeter|-|32bit
configuring for 44100Hz, period = 256 frames (5.8 ms), buffer = 2 periods
ALSA: final selected sample format for capture: 32bit integer little-endian
ALSA: use 2 periods for capture
ALSA: final selected sample format for playback: 32bit integer little-endian
ALSA: use 2 periods for playback
ALSA lib seq_hw.c:466:(snd_seq_hw_open) open /dev/snd/seq failed: Permission denied
failed to open alsa seq
ALSA: cannot attach MIDI: -13
22:19:03.336 JACK connection change.
22:19:03.337 Server configuration saved to "/home/arthur/.jackdrc".
22:19:03.337 Statistics reset.
22:19:03.345 Client activated.
22:19:03.345 Patchbay deactivated.
22:19:03.422 JACK connection graph change.
Cannot lock down 107341338 byte memory area (Kan inte allokera minne)

This is a multiboot Fujitsu Esprimo, intel i5, 12  GB ram, latest updated 3 weeks ago  I have noticed similar problems under Manjaro (updated today) and I wonder whether I should somehow test my hardware. I have been using Rosegarden with my midi keyboard as midi output for years and only used Qsynth a few times, and don't even remember under which distro it was.

Now I am starting to edit a large number of '.rg' files I recorded in Rosegarden through those years and would like to be able to do it away from my midi keyboard,  using QSynth.  I tried to load different sound fonts in QSynth, and now I am starting it without pre-setting any sound font, but I think this does not matter.

I can't make any sense out of these messages.  Will be thankful for any tips.