Knxd crash after sending 2 ON / OFF commands via PAPERUI or knxtool

Hi,
I have just completed the installation of openhabian on Raspberry 3B with the KNXD service in order to use a Zennio USB interface (which I have available for testing) instead of the classic IP Router.
I think I have correctly configured the Gateway and the first Item linked to a Thing (knx actuator) via PAPER UI, because through file (knx.item knx.thing) I have not yet learned the correct syntax.

In the PAPER UI web page, by clicking on the Item I can turn the light on and off, but at the third command nothing happens on the system, only on the web page the switch shows the change of state.

Same thing if I use in knxtool groupswrite command

I report what is displayed by the terminal before and after the malfunction.

[17:25:51] openhabian@openhab:~$ systemctl status knxd
● knxd.service - KNX Daemon
   Loaded: loaded (/lib/systemd/system/knxd.service; enabled; vendor preset: enabled)
   Active: active (running) since Sun 2020-03-29 17:23:31 CEST; 2min 23s ago
  Process: 552 ExecStart=/usr/local/bin/knxd -p /run/knxd/knxd.pid $KNXD_OPTIONS (code=exited, status=0/SUCCESS)
 Main PID: 554 (knxd)
    Tasks: 2 (limit: 2319)
   Memory: 2.9M
   CGroup: /system.slice/knxd.service
           └─554 /usr/local/bin/knxd -p /run/knxd/knxd.pid --eibaddr=1.1.128 --client-addrs=1.1.129:8 -d -D -T -R -S -i --listen-local

mar 29 17:23:31 openhab systemd[1]: Starting KNX Daemon...
mar 29 17:23:31 openhab systemd[1]: knxd.service: Can't open PID file /run/knxd/knxd.pid (yet?) after start: No such file or directory
mar 29 17:23:31 openhab systemd[1]: Started KNX Daemon.

[17:25:57] openhabian@openhab:~$ knxtool groupswrite ip:localhost 1/1/1 1
Send request
[17:26:00] openhabian@openhab:~$ knxtool groupswrite ip:localhost 1/1/1 0
Send request
[17:26:04] openhabian@openhab:~$ knxtool groupswrite ip:localhost 1/1/1 1
Send request
[17:26:07] openhabian@openhab:~$ systemctl status knxd
● knxd.service - KNX Daemon
   Loaded: loaded (/lib/systemd/system/knxd.service; enabled; vendor preset: enabled)
   Active: failed (Result: exit-code) since Sun 2020-03-29 17:26:08 CEST; 5s ago
  Process: 552 ExecStart=/usr/local/bin/knxd -p /run/knxd/knxd.pid $KNXD_OPTIONS (code=exited, status=0/SUCCESS)
 Main PID: 554 (code=exited, status=1/FAILURE)

mar 29 17:23:31 openhab systemd[1]: Starting KNX Daemon...
mar 29 17:23:31 openhab systemd[1]: knxd.service: Can't open PID file /run/knxd/knxd.pid (yet?) after start: No such file or directory
mar 29 17:23:31 openhab systemd[1]: Started KNX Daemon.
mar 29 17:26:08 openhab systemd[1]: knxd.service: Main process exited, code=exited, status=1/FAILURE
mar 29 17:26:08 openhab systemd[1]: knxd.service: Failed with result 'exit-code'.

Note: I still don’t understand the reason for that “knxd.service: Can’t open PID file /run/knxd/knxd.pid (yet?) After start: No such file or directory” message, and there seem to be no people in able to help me on the forum, but nevertheless the system seems to work (at least temporarily).

If I try to restart KNXD with systemctl restart knxd sometimes I can control againn the light, sometimes I can’t.
If I restart openhab with sudo reboot now it obviously starts working again, but only for two or three commands, no more.

I accept suggestions for resolving the situation. I also evaluate alternative solutions to the one I use, if from your experience it is more reliable

Try cleaning the cache and restarting OH 2 times.

sudo systemctl stop openhab2

sudo openhab-cli clean-cache

sudo systemctl start openhab2

For restarts
sudo systenctl restart openhab2

Make sure that OH has fully restarted between each restart and after cleaning the cache OH will take a few minuets to get up and running.

If that does not work then try uninstalling/reinstalling the binding.

Hi H102,
I tried with the commands you suggested, waiting for OH to restart (checking through web pages that all the graphic interfaces were available) but nothing changes, not even reinstalling the knx binding.
The only way I can restore it is to restart knxd with systemctl restart knxd.

Can it be a problem related to the USB interface? I have read something about the reliability of these devices but my technical knowledge (a knowledge of technical English) is limited.