[SOLVED] Trådfri throws error message but functions well

Update: I cleared the cache and restarted OH twice. This made the problem go away!

I installed the Trådfri GW, a remote control and an RGB light a couple of days ago, using the Paper UI. Everything went well and was quite easy to do. The light works as expected. But the GW generates an error message once every minute. See below. The GW version is 1.10.29 and I am running OH 2.5.2 release version.

2020-03-23 10:05:54.839 [WARN ] [.eclipse.californium.core.CoapClient] - exception while handling response

java.lang.IllegalStateException: Not a JSON Array: {"9078":1,"9023":"0.tradfri.pool.ntp.org","9059":1584954354,"9060":"2020-03-23T09:05:54.042784Z","9062":0,"9066":5,"9061":0,"9029":"1.10.29","9106":0,"9075":0,"9081":"7e3765520440008c","9082":false,"9093":0,"9083":"N/A","9054":0,"9055":0,"9069":1584719623,"9071":1,"9072":3,"9073":29,"9074":1,"9092":0,"9200":"5c936dbf-037d-4e92-b92a-f43ee04945f9","9076":10,"9079":0,"9077":25,"9103":"","9080":60,"9118":0,"9105":0,"9107":0,"9201":2,"9202":1584719800}

at com.google.gson.JsonElement.getAsJsonArray(JsonElement.java:107) ~[?:?]

at org.openhab.binding.tradfri.internal.handler.TradfriGatewayHandler.onUpdate(TradfriGatewayHandler.java:314) ~[?:?]

at org.openhab.binding.tradfri.internal.TradfriCoapHandler.onLoad(TradfriCoapHandler.java:73) ~[?:?]

at org.eclipse.californium.core.CoapClient$MessageObserverImpl.deliver(CoapClient.java:1466) ~[bundleFile:?]

at org.eclipse.californium.core.CoapClient$MessageObserverImpl$1.run(CoapClient.java:1448) [bundleFile:?]

at org.eclipse.californium.core.CoapClient.execute(CoapClient.java:1289) [bundleFile:?]

at org.eclipse.californium.core.CoapClient$MessageObserverImpl.succeeded(CoapClient.java:1444) [bundleFile:?]

at org.eclipse.californium.core.CoapClient$MessageObserverImpl.onResponse(CoapClient.java:1434) [bundleFile:?]

at org.eclipse.californium.core.coap.Request.setResponse(Request.java:711) [bundleFile:?]

at org.eclipse.californium.core.network.EndpointManager$ClientMessageDeliverer.deliverResponse(EndpointManager.java:272) [bundleFile:?]

at org.eclipse.californium.core.network.stack.BaseCoapStack$StackTopAdapter.receiveResponse(BaseCoapStack.java:210) [bundleFile:?]

at org.eclipse.californium.core.network.stack.AbstractLayer.receiveResponse(AbstractLayer.java:89) [bundleFile:?]

at org.eclipse.californium.core.network.stack.ExchangeCleanupLayer.receiveResponse(ExchangeCleanupLayer.java:93) [bundleFile:?]

at org.eclipse.californium.core.network.stack.ObserveLayer.receiveResponse(ObserveLayer.java:150) [bundleFile:?]

at org.eclipse.californium.core.network.stack.BlockwiseLayer.receiveResponse(BlockwiseLayer.java:676) [bundleFile:?]

at org.eclipse.californium.core.network.stack.ReliabilityLayer.receiveResponse(ReliabilityLayer.java:305) [bundleFile:?]

at org.eclipse.californium.core.network.stack.AbstractLayer.receiveResponse(AbstractLayer.java:89) [bundleFile:?]

at org.eclipse.californium.core.network.stack.BaseCoapStack.receiveResponse(BaseCoapStack.java:139) [bundleFile:?]

at org.eclipse.californium.core.network.CoapEndpoint$1.receiveResponse(CoapEndpoint.java:277) [bundleFile:?]

at org.eclipse.californium.core.network.UdpMatcher$4.run(UdpMatcher.java:399) [bundleFile:?]

at org.eclipse.californium.elements.util.SerialExecutor$1.run(SerialExecutor.java:276) [bundleFile:?]

at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [?:1.8.0_232]

at java.util.concurrent.FutureTask.run(FutureTask.java:266) [?:1.8.0_232]

at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180) [?:1.8.0_232]

at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293) [?:1.8.0_232]

at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:1.8.0_232]

at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:1.8.0_232]

at java.lang.Thread.run(Thread.java:748) [?:1.8.0_232]

I have also started to receive this.
Did you find out what it was?

/Mike

No. After clearing the cache and a restart this has not come back.

I have the same issue, but I guess the problem is not solved just by clearing the cache. It will come back. Does anybody found a real solution?