NetWorker: vCenter Plugin installation fails with "Unable to install the plug-in as an error occurred while retrieving the token/session ID"

The NetWorker VMware Protection (NVP) integration is configured with the vProxy Appliance. The NetWorker Management Web User Interface (NWUI) is used to install the vCenter Server plug-in. The vCenter Server plug-in fails with:

Registration of vCenter [ ] failed. See log for further details.
Unable to install the plug-in as an error occured while retrieving the token/session ID
See vcui.log file in the NetWorker tomcat logs folder for further details.

The NetWorker Server restapi.log shows:

Linux: /nsr/logs/restapi/restapi.log
Windows: [INSTALL_DRIVE]:\Program Files\EMC NetWorker\nsr\logs\restapi\restapi.log

YYYYY-MM-DD HH:MM:SS ERROR [ ] c.e.n.w.WebApiExceptionMapper - Status 'Internal Server Error', msg: Unable to install the plug-in as an error occured while retrieving the token/session ID
com.emc.nw.webapi.exception.InternalServerErrorException: Unable to install the plug-in as an error occured while retrieving the token/session ID

An authentication token was issued to the NetWorker user account using the nsrlogin command. These tokens are time-based. The error appears after the token has expired.

Re-establish NetWorker authentication trust and generate a new user security token. 

1. Run nsrauthtrust from the NetWorker Server and provide the authentication server: nsrauthtrust -H my_authentication_server -P 9090
2. Use one of the following options:

• Clear the expired token: nsrlogout
• Generate a new user security token for the NetWorker User: nsrlogin -u myuser 

3. Attempt the vSphere plugin installation from NWUI again.

• NetWorker: nsr commands fail when logged as root or Administrator command prompt.