Description:-
The BusinessConnect (BC) Interior Server (IS) fails to start with ddtp error: 

Error:-
java.lang.RuntimeException: com.tibco.ax.fw.runtime.impl.GtwyException: Data Port error connecting to Gateway Server
    at com.tibco.ax.fw.runtime.inbound.impl.IBMSHService$FetchFileThread.doUnitOfWork(IBMSHService.java:2574)
    at com.tibco.ax.fw.runtime.impl.AbstractService$MessageCallbackThread.run(AbstractService.java:1419)
    at com.tibco.pe.util.ThreadPool$ThreadPoolThread.run(Unknown Source)
Caused by: com.tibco.ax.fw.runtime.impl.GtwyException: Data Port error connecting to Gateway Server
    at com.tibco.ax.fw.runtime.inbound.impl.IBMSHService$FetchFileThread.doUnitOfWork(IBMSHService.java:2572)
    ... 2 more
Caused by: java.lang.IllegalStateException: Scheme 'https' not registered.
    at org.apache.http.conn.scheme.SchemeRegistry.getScheme(SchemeRegistry.java:71)
    at org.apache.http.impl.conn.DefaultHttpRoutePlanner.determineRoute(DefaultHttpRoutePlanner.java:111)
    at org.apache.http.impl.client.DefaultRequestDirector.determineRoute(DefaultRequestDirector.java:709)
    at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:356)
    at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:820)
    at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:754)
    at com.tibco.ax.fw.webengine.client.WebClient.perform(WebClient.java:275)
    at com.tibco.ax.fw.runtime.inbound.impl.IBMSHService$FetchFileThread.fetchData(IBMSHService.java:2493)
    at com.tibco.ax.fw.runtime.inbound.impl.IBMSHService$FetchFileThread.doUnitOfWork(IBMSHService.java:2563)
    ... 2 more

This error will only occur when using plain HTTP data transfers between the IS and GS, which is enabled by setting "bc.ib.channel.force.plain" property in TIBCO Administrator GUI under 
BusinessConnect > System Settings > Activated Protocol Plug-ins and Properties 
> BC.

This error occurs when the corresponding value "java.property.bc.ib.channel.force.plain" is not set to true in all gsengine.tra files. Correcting this value will resolve the issue.