We upgraded our TRAIN environment to 16.1.1 from 16.0.3 patch 1.
Finally once the upgrade completed, we started the services and found that one of the app service (app2) says 'Started' but the logs show otherwise.
Release : 16.1.1
This is caused by a bind address conflict.
SEVERE: Failed to create server shutdown socket on address [localhost] and port [23793] (base port [23793] and offset [0])
java.net.BindException: Address already in use (Bind failed)
The PPMBROKER service also uses 23793 RMI port. In case that service started APP2 service fails to start.
Change the RMI port of APP2 or PPMBROKER service to resolve the issue.