When setting-up APM Mobile REST service on it's own port 81, we set the netsh port authorization for that port.
Mobile REST service must be assigned to an open port and cannot itself have authorization set for the service/system user because this interferes with the Mobile REST Service which needs the port to be unowned. Use netsh show to review the ports for potential authorizations, and netsh delete on port used by Mobile REST to remove authorization. Then verify that the webmonitor was available and that the webservice for Mobile REST is listening.
https://communities.bentley.com/products/assetwise/asset_performance_management/w/wiki/39594/apm-mobile-rest-service-does-not-run-due-to-port-conflict
SR 7001086150