3391244 - Unable to open connection to backend system: error 110 - Connection timed out: /<ip address>

Application is unable to fetch data from the backend system through SAP Cloud Connector. The following error messages are seen in the ljs_trace.log (<2.17)/scc_core.trc (>=2.17) file of SAP Cloud Connector:

<>#ERROR#com.sap.core.connectivity.spi.processing.AbstractProtocolProcessor#tunnel-client-19-4##Unable to open connection to backend system: error 110 - Connection timed out: /<ip address>
io.netty.channel.AbstractChannel$AnnotatedConnectException: error 110 - Connection timed out: /<ip address>
Caused by: java.net.ConnectException: error 110 - Connection timed out
    at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
    at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:731)
    at io.netty.channel.socket.nio.NioSocketChannel.doFinishConnect(NioSocketChannel.java:337)
    at io.netty.channel.nio.AbstractNioChannel$AbstractNioUnsafe.finishConnect(AbstractNioChannel.java:334)
    at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:776)
    at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:724)
    at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:650)
    at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:562)
    at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:997)
    at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
    at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
    at java.lang.Thread.run(Thread.java:838)

**Image/data in this KBA is from SAP internal systems, sample data, or demo systems. Any resemblance to real data is purely coincidental.

SAP Cloud Connector release independent.

 error 110, Connection timed out, backend, Cloud Connector, SCC, Network issue, error, SAP Cloud Connector, SCC, backend connectivity issue, network interruption, proxy settings, firewall configuration, idle timeout, principal propagation failure, login popup, backend inaccessible, connection timed out error 110, ljs_trace.log, scc_core.trc, Netty connection exception, tunnel client error, application data fetch failure, SAP HEC, PCO-OPS, network intermediary issue, backend connection troubleshooting, SAP BTP connectivity, connectivity timeout, Java ConnectException, backend system access, firewall idle timeout configuration, , KBA , BC-MID-SCC , SAP Cloud Connector On-Demand/On-Premise Connectivity , Problem