unable to monitor webserver with Infrastructure Agent

Products

• CA Application Performance Management (APM / Wily / Introscope)

Issue/Introduction

Have configured the WebServer monitoring with APMIA agent. 

The WebServerConfig.xml file has not changed.

<WebServer Type="Apache" Enabled="true" Protocol="TLS" ServerURL="https://<hostname>:443" DisplayName="appserver.xom" Mode="Permissive"/>

Error about "hostPort" but do not see this as an attribute.

[DEBUG] [IntroscopeAgent.ProbeCollector] Failed to parse number string for hostPort; default hostPort value to 80.java.lang.NumberFormatException: Cannot parse null string
        at java.base/java.lang.Integer.parseInt(Unknown Source)
        at java.base/java.lang.Integer.parseInt(Unknown Source)
        at com.wily.introscope.agent.collector.ProbeCollector.checkForSpecialTracers(ProbeCollector.java:340)
        at com.wily.introscope.agent.collector.ProbeCollector.processFunctionStartMessage(ProbeCollector.java:670)
        at com.wily.introscope.agent.collector.ProbeCollector.processDataMessage(ProbeCollector.java:552)
        at com.wily.introscope.agent.collector.ProbeCollector.processMessage(ProbeCollector.java:496)
        at com.wily.introscope.agent.arf.ArfDataConnection.processMessage(ArfDataConnection.java:117)
        at com.wily.introscope.agent.arf.AArfConnection.runReader(AArfConnection.java:311)
        at com.wily.introscope.agent.arf.AArfConnection.access$000(AArfConnection.java:39)
        at com.wily.introscope.agent.arf.AArfConnection$1.run(AArfConnection.java:226)
        at java.base/java.lang.Thread.run(Unknown Source)

Resolution

virtual host section for the machine name was missing so the server-status failed.  
added virtual host section for the machine name and now Infrastructure Agent is working good for WebServer monitoring.