After modifying the default WebView listening port value for the property "introscope.webview.tcp.port" in the IntroscopeWebView.properties file, the new WebView URL (http://<hostname>:<port>) fails with error "HTTP ERROR 500".
The root cause of the error is an osgi cache problem and can be resolved as follows:
1. Stop the Standalone/MOM Enterprise Manager and WebView processes
2. Go to EM_HOME/product/webview/configuration and Delete these 4 directories:
DO NOT delete the file config.ini
3. If directory EM_HOME/work exists, then also delete its contents
4. Restart Standalone/MOM Enterprise Manager and WebView processes
5. Relaunch the Webview URL and the problem should be resolved