2708278 - AS Java HTTP Destination ping operation to SLD fails - Unable to open connection to proxy - HttpException - Connection refused

As part of configuring the SLD Data Supplier Destination, maintaining the HTTP destination for the SLD data supplier in NWA, the following error is received after Ping Destination:

Error during ping operation: Error while silently connecting: org.w3c.www.protocol.http.HttpException: Connection refused (Connection refused) (local port XXXXX to address 0:0:0:0:0:0:0:0, remote port 80 to address 127.0.0.1 (localhost))

The whole belonging exception can be found and looks like below in the defaultTrace files:

[...]
Error during ping operation: Error while silently connecting: org.w3c.www.protocol.http.HttpException: Connection refused (Connection refused) (local port 34689 to address 0:0:0:0:0:0:0:0, remote port 80 to address 127.0.0.1 (localhost))
[EXCEPTION]
com.sap.security.wd.destinations.exception.DestinationUIException: com.sap.tc.lm.itsam.ui.proxy.exception.JMXJMRuntimeOperationException: com.sap.security.core.server.destinations.itsam.DestinationRuntimeException: com.sap.security.core.server.destinations.api.DestinationException: [com.sap.ASJ.dest.if0156] Error during ping operation: Error while silently connecting: org.w3c.www.protocol.http.HttpException: Connection refused (Connection refused) (local port 34689 to address 0:0:0:0:0:0:0:0, remote port 80 to address 127.0.0.1 (localhost))
 at com.sap.security.wd.destinations.helper.BEInstructor.pingDestination(BEInstructor.java:264)
 at com.sap.security.wd.destinations.http.HTTPDestMaintComp.pingDestination(HTTPDestMaintComp.java:421)
 at com.sap.security.wd.destinations.http.wdp.InternalHTTPDestMaintComp.wdInvokeMethod(InternalHTTPDestMaintComp.java:389)
 at com.sap.tc.webdynpro.progmodel.generation.ExternalControllerPI$ExternalInterfaceInvocationHandler.invoke(ExternalControllerPI.java:339)
 at com.sun.proxy.$Proxy734.pingDestination(Unknown Source)
 at com.sap.security.wd.destinations.main.MainComp.pingDestination(MainComp.java:361)
[...]

In addition, in the SLD, when clicking on "Collect and Send Data", the following error is received:

Collect and Send Data failed: Data transfer failed. Unable to open connection to proxy "<host>:80. The host is down or unavailable..

• SAP NW Application Server Java
• System Landscape Directory

Error, ping, operation, destinatioon, http destination, SLD, Connection refused, remote port 80, Unable to open connection to proxy, http.proxySet, http.proxyHost, http.proxyPort, https.proxyHost, https.proxyPort, http.nonProxyHosts, https.nonProxyHosts, Collect and Send Data , KBA , BC-JAS-SEC , Security, User Management , BC-CCM-SLD , System Landscape Directory / Component Repository , Problem