Bluetooth error "Unable to load key file"

I am on 22.04 and I have an error with my bluetooth. I can turn Bluetooth on, I can see other Bluetooth device to connect with, but I cannot connect. The toggle Connection doesn't work.

Running sudo systemctl status bluetooth.service returns the following:

● bluetooth.service - Bluetooth service
     Loaded: loaded (/lib/systemd/system/bluetooth.service; enabled; vendor preset: enabled)
     Active: active (running) since Wed 2023-02-01 12:22:59 EET; 12min ago
       Docs: man:bluetoothd(8)
   Main PID: 7426 (bluetoothd)
     Status: "Running"
      Tasks: 1 (limit: 38166)
     Memory: 808.0K
        CPU: 95ms
     CGroup: /system.slice/bluetooth.service
             └─7426 /usr/lib/bluetooth/bluetoothd

systemd[1]: Starting Bluetooth service...
bluetoothd[7426]: Bluetooth daemon 5.64
systemd[1]: Started Bluetooth service.
bluetoothd[7426]: Starting SDP server
bluetoothd[7426]: Bluetooth management interface 1.21 initialized
bluetoothd[7426]: src/device.c:load_gatt_db() Unable to load key file from /var/lib/bluetooth/84:5C:F3:92:6F:4D/cache/6E:92:30:B5:4A:0D: (No such file or directory)
bluetoothd[7426]: src/device.c:load_gatt_db() No cache for 6E:92:30:B5:4A:0D
bluetoothd[7426]: Too small Add Device complete event

Edit:

The output of sudo dmesg | grep -i blue is:

[    3.356236] Bluetooth: Core ver 2.22
[    3.356430] NET: Registered PF_BLUETOOTH protocol family
[    3.356431] Bluetooth: HCI device and connection manager initialized
[    3.356433] Bluetooth: HCI socket layer initialized
[    3.356434] Bluetooth: L2CAP socket layer initialized
[    3.356447] Bluetooth: SCO socket layer initialized
[    3.427475] Bluetooth: hci0: Legacy ROM 2.x revision 5.0 build 25 week 20 2015
[    3.428603] Bluetooth: hci0: Intel Bluetooth firmware file: intel/ibt-hw-37.8.10-fw-22.50.19.14.f.bseq
[    3.662489] Bluetooth: hci0: Intel BT fw patch 0x43 completed & activated
[    3.996584] Bluetooth: BNEP (Ethernet Emulation) ver 1.3
[    3.996587] Bluetooth: BNEP filters: protocol multicast
[    3.996589] Bluetooth: BNEP socket layer initialized
[  410.123831] Bluetooth: hci0: link tx timeout

I encountered the same problem today when I tried to pair my bluetooth mouse on both Windows and Ubuntu of the same PC. I renamed /var/lib/bluetooth/PC:MAC:ADDRESS/MOUSE:MAC:ADDRESS to match the mouse address on Windows, and when I restart bluetooth.service, it fails with "Unable to load key file" error. Turns out there need to be a cached attribute file in /var/lib/bluetooth/PC:MAC:ADDRESS/cache directory, which should match the name and content of MOUSE:MAC:ADDRESS directory too. So I have to remove MOUSE:MAC:ADDRESS directory (which in your case is 6E:92:30:B5:4A:0D), restart bluetooth service, and everything works fine again (though I still have to repair my mouse).

Note that removing this directory requires sudo -i first.