Connection to KNX binding is closed after maximum attempts are sent

Add-ons Bindings
1

I would like to add a second KNX interface to my OpenHAB configuration. The first KNX interface is defined as follows and works perfectly:

Bridge knx:ip:bridge [
    ipAddress="172.16.30.18",
    portNumber=3671,
    localIp="172.16.30.11",
    type="TUNNEL",
    readingPause=50, 
    responseTimeout=10,
    readRetriesLimit=3,
    autoReconnectPeriod=1,
    localSourceAddr="0.0.0"
]

{ 
}

For testing purposes, I’ve renamed my knx.things file to knx.things.old and created a new knx.2nd.things file. The 2nd KNX interface is linked to an ISE Smart Connect KNX interface. The configuration is as follows:

Bridge knx:ip:bridge [
    ipAddress="172.16.30.37",
    type="TUNNEL"
]

{   
}

I receive the following error in openhab.log

2022-03-29 21:37:48.307 [INFO ] [el.core.internal.ModelRepositoryImpl] - Loading model 'knx.2nd.things'
2022-03-29 21:38:50.420 [ERROR] [NXnet/IP Tunneling 172.16.30.37:3671] - close connection - maximum send attempts
tuwien.auto.calimero.KNXAckTimeoutException: maximum send attempts, no service acknowledgment received
        at tuwien.auto.calimero.knxnetip.ConnectionBase.send(ConnectionBase.java:253) ~[?:?]
        at tuwien.auto.calimero.knxnetip.KNXnetIPTunnel.send(KNXnetIPTunnel.java:213) ~[?:?]
        at tuwien.auto.calimero.link.KNXNetworkLinkIP.onSend(KNXNetworkLinkIP.java:423) ~[?:?]
        at tuwien.auto.calimero.link.AbstractLink.send(AbstractLink.java:385) ~[?:?]
        at tuwien.auto.calimero.link.KNXNetworkLinkIP.sendRequestWait(KNXNetworkLinkIP.java:402) ~[?:?]
        at tuwien.auto.calimero.process.ProcessCommunicatorImpl.send(ProcessCommunicatorImpl.java:461) ~[?:?]
        at tuwien.auto.calimero.process.ProcessCommunicatorImpl.readFromGroup(ProcessCommunicatorImpl.java:430) ~[?:?]
        at tuwien.auto.calimero.process.ProcessCommunicatorImpl.read(ProcessCommunicatorImpl.java:352) ~[?:?]
        at org.openhab.binding.knx.internal.client.AbstractKNXClient.readNextQueuedDatapoint(AbstractKNXClient.java:289) ~[?:?]
        at org.openhab.binding.knx.internal.client.AbstractKNXClient.lambda$1(AbstractKNXClient.java:200) ~[?:?]
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515) [?:?]
        at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:305) [?:?]
        at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:305) [?:?]
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) [?:?]
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) [?:?]
        at java.lang.Thread.run(Thread.java:829) [?:?]

I’ve installed an app on my smartphone (Easy KNX Lite) to test the IP address of the KNX interface. With this app I was able to switch a light. This proofs that my settings should be correct.

What can be wrong?

Ivan