Trouble connecting Xiaomi Aqara switch using Zigbee Binding + Qivicon Dongle

I just received a bunch of new smart devices that want to be set up, but unfortunately, I struggle connecting my new Aqara Double Switch D1 which uses Zigbee. Another of my new tools is the Qivicon Dongle which I already set up with the Zigbee Binding and successfully used to connect another Zigbee Bulb. However, I did not yet have success with the Aqara Switch …

Short story: Currently, it simply does not appear in the inbox when pressing both buttons. In the past, however, it did.

Long story:
If I press both buttons of the switch for ca. 10 seconds, both LEDs start blinking for a few seconds. During my first attempts, I could see an “Unknown Zigbee Device” in the Paper UI Inbox, and I spent some attempts on adding this thing and removing it again because it showed the status “OFFLINE - HANDLER_INITIALIZATION_ERROR”.
After giving the Paper UI some more time for identifying the device, it was also able to determine a less generic name (which I, unfortunately, don’t remember). But because it still showed to initialization error, I removed it again …
However, after some attempts, I saw that the switch immediately appeared in the inbox before I pressed it, so it was probably cached. Thus I removed it manually from the JSONDB file (/var/lib/openhab2/jsondb/org.eclipse.smarthome.core.thing.Thing.json). After this, I could find it again in the inbox, but after some more attempts, it cannot be found any longer …

I already:

  • rebooted my openHABpi multiple times
  • cleared the cache
  • I read that the Aqara devices use to “quickly go into sleep mode and thus you must keep them upwake”, so I pressed the buttons randomly during initialization, but it did not help, either.
  • Could there be some cache in the Qivicon Stick (I have no idea how it works)? If yes, how could I reset it?

What could I try else? Any help would be so much appreciated!

Related threads:

Sorry for pushing my own thread, but I have very little experience with Zigbee at all, and am sure that any basic pointers about how to reset the devices cache would help me a lot. Thanks in advance!