Use Case: 
1. log in to Digital Workplace and submit a request against Catalog Service.
2. From Catalog -> Reports -> Service Request -> Filter -> Failed Request

3. View Details -> Error tab

com.bmc.myservice.common.util.exception.MyServiceException: [ERROR (38): An error occured when invoking the custom action. Unable to update the database.]
at com.bmc.myservice.common.util.exception.MyServiceExceptionUtils.rethrowRxException(MyServiceExceptionUtils.java:38)
at com.bmc.myservice.common.util.SrvInterceptor.invoke(SrvInterceptor.java:31)
at com.sun.proxy.$Proxy269.startProcessInstance(Unknown Source)
at com.bmc.myservice.servicerequest.RegularSbeRequestHandlingStrategy$1.lambda$call$0(RegularSbeRequestHandlingStrategy.java:320)
at com.bmc.myservice.servicerequest.ServiceRequestSrvImpl.withServiceRequestThreadLocal(ServiceRequestSrvImpl.java:5055)
at com.bmc.myservice.servicerequest.RegularSbeRequestHandlingStrategy$1.call(RegularSbeRequestHandlingStrategy.java:319)
at com.bmc.myservice.servicerequest.RegularSbeRequestHandlingStrategy$1.call(RegularSbeRequestHandlingStrategy.java:305)
at com.bmc.myservice.common.util.HttpCallContext.lambda$wrapWithClonedHttpCallContext$1(HttpCallContext.java:140)
at com.bmc.myservice.common.background.BackgroundAutomationMark.lambda$wrapWithInheritedMark$0(BackgroundAutomationMark.java:43)
at com.bmc.myservice.common.background.BackgroundTaskUtils.lambda$1(BackgroundTaskUtils.java:153)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
at java.base/java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:304)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
at java.base/java.lang.Thread.run(Thread.java:834)

Caused by: java.lang.reflect.InvocationTargetException
at jdk.internal.reflect.GeneratedMethodAccessor1914.invoke(Unknown Source)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:566)
at com.bmc.arsys.server.rx.services.action.DefaultCustomActionExecutor.invokeMethod(DefaultCustomActionExecutor.java:516)
... 472 more
Caused by: javax.ws.rs.ProcessingException: java.net.ConnectException: Connection refused (Connection refused)
at org.glassfish.jersey.client.internal.HttpUrlConnector.apply(HttpUrlConnector.java:287)
at org.glassfish.jersey.client.ClientRuntime.invoke(ClientRuntime.java:255)
at org.glassfish.jersey.client.JerseyInvocation$1.call(JerseyInvocation.java:684)
at org.glassfish.jersey.client.JerseyInvocation$1.call(JerseyInvocation.java:681)
at org.glassfish.jersey.internal.Errors.process(Errors.java:315)
at org.glassfish.jersey.internal.Errors.process(Errors.java:297)
at org.glassfish.jersey.internal.Errors.process(Errors.java:228)
at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:444)
at org.glassfish.jersey.client.JerseyInvocation.invoke(JerseyInvocation.java:681)
at com.bmc.myservice.connect.rest.service.RequestExecutor$1.call(RequestExecutor.java:79)
at com.bmc.myservice.connect.rest.service.RequestExecutor$1.call(RequestExecutor.java:76)
at com.bmc.myservice.connect.rest.service.RestOperationRetryOnExceptionStrategy.run(RestOperationRetryOnExceptionStrategy.java:33)
at com.bmc.myservice.connect.rest.service.RequestExecutor.execute(RequestExecutor.java:75)
at com.bmc.myservice.connect.rest.service.RestService.sendHttpRequest(RestService.java:129)
... 476 more
Caused by: java.net.ConnectException: Connection refused (Connection refused)
at java.base/java.net.PlainSocketImpl.socketConnect(Native Method)
at java.base/java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:399)
at java.base/java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:242)
at java.base/java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:224)
at java.base/java.net.SocksSocketImpl.connect(SocksSocketImpl.java:403)
at java.base/java.net.Socket.connect(Socket.java:609)
at java.base/sun.security.ssl.SSLSocketImpl.connect(SSLSocketImpl.java:289)
at java.base/sun.net.NetworkClient.doConnect(NetworkClient.java:177)
at java.base/sun.net.www.http.HttpClient.openServer(HttpClient.java:474)
at java.base/sun.net.www.http.HttpClient.openServer(HttpClient.java:569)
at java.base/sun.net.www.protocol.https.HttpsClient.<init>(HttpsClient.java:265)
at java.base/sun.net.www.protocol.https.HttpsClient.New(HttpsClient.java:372)
at java.base/sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.getNewHttpClient(AbstractDelegateHttpsURLConnection.java:191)
at java.base/sun.net.www.protocol.http.HttpURLConnection.plainConnect0(HttpURLConnection.java:1187)
at java.base/sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:1081)
at java.base/sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(AbstractDelegateHttpsURLConnection.java:177)
at java.base/sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1592)
at java.base/sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1520)
at java.base/java.net.HttpURLConnection.getResponseCode(HttpURLConnection.java:527)
at java.base/sun.net.www.protocol.https.HttpsURLConnectionImpl.getResponseCode(HttpsURLConnectionImpl.java:334)
at org.glassfish.jersey.client.internal.HttpUrlConnector._apply(HttpUrlConnector.java:394)
at org.glassfish.jersey.client.internal.HttpUrlConnector.apply(HttpUrlConnector.java:285)
... 489 more

The error indicates a connection refused error that indicates a connectivity issue. In this case, the connector configured in the digital workplace catalog trying to connect to the customer environment through gateway fails.
To validate connectivity, perform the below steps.

1. Login to Catalog -> Services -> Connector -> select the connector in picture.
2. Note down the hostname and port number.
3. Connect to the rancher and access digital workplace catalog POD.
4. Test the connectivity by using the telnet command as below.

telnet [servername] [port]

This indicates a failure. Engage Wintel Team to confirm if the host name and port number used shows any request on server gateway end log.

A Successful connection looks like below.

Solution:
The Port number in the connector was used wrong. The Wintel team confirmed the port number to use was different.

To Fix:
- In Catalog Connector -> Configure correct port number (5045) and check connectivity with telnet command.