Cipher problem initializing a Tradfi gateway

Platform information:

  • Raspberry Pi 3B+, 1GB RAM, plenty space on SSD
  • OS Raspbian, latest version fully up to date
  • Java Runtime Environment: Oracle Java 8:
    java version “1.8.0_241”
    Java™ SE Runtime Environment (build 1.8.0_241-b07)
    Java HotSpot™ Client VM (build 25.241-b07, mixed mode)
  • openHAB version:
    openhab-distro : 2.5.2
    openhab-core : 2.5.0
    openhab1-addons : 1.14.0
    openhab2-addons : 2.5.2
    karaf : 4.2.7
  • IKEA TRÅDFRI gateway firmware version 1.10.29
  • Issue of the topic: IKEA TRÅDFRI gateway initialization fails
    Attempting to configure this gateway device using the IKEA TRÅDFRI binding. It appears to be automatically discovered, and I’ve edited the thing’s configuration to supply the security code, but its status never moves from “Initializing”. Looking at the log, I see the following two messages:
2020-03-03 19:05:19.436 [INFO ] [g.discovery.internal.PersistentInbox] - Added new thing 'tradfri:gateway:gwe8e8b7b9a667' to inbox.
2020-03-03 19:06:20.289 [WARN ] [mmon.WrappedScheduledExecutorService] - Scheduled runnable ended with an exception: 
java.lang.IllegalStateException: Supported cipher suites must be set either explicitly or implicitly by means of setting the identity or PSK store
	at org.eclipse.californium.scandium.config.DtlsConnectorConfig$ ~[?:?]
	at org.openhab.binding.tradfri.internal.handler.TradfriGatewayHandler.obtainIdentityAndPreSharedKey( ~[?:?]
	at org.openhab.binding.tradfri.internal.handler.TradfriGatewayHandler.lambda$0( ~[?:?]
	at java.util.concurrent.Executors$ ~[?:1.8.0_241]
	at ~[?:1.8.0_241]
	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201( ~[?:1.8.0_241]
	at java.util.concurrent.ScheduledThreadPoolExecutor$ ~[?:1.8.0_241]
	at java.util.concurrent.ThreadPoolExecutor.runWorker( [?:1.8.0_241]
	at java.util.concurrent.ThreadPoolExecutor$ [?:1.8.0_241]
	at [?:1.8.0_241]

I have no idea what that means or how to go about resolving it. Can anyone suggest what I should do?