vCenter does not allow underscore usage in either host names or domain names, and this restriction also carries over to user names.
If a user name is created with an underscore in the "add array" section of the plugin it will error out with an error similar to below in the virgo logs:
https://VCENTER_PROD.EXAMPLE.COM:12443>/vmwb/logbrowser: Host name may not be null
ERROR [ERROR] http-bio-9443-exec-8 System.err java.lang.IllegalArgumentException: Host name may not be null
ERROR [ERROR] http-bio-9443-exec-8 com.vmware.loganalyzer.provider.LogBrowserServiceImpl Error when searching service in LookupService, urn:logbrowser:logbrowser java.lang.Exception:
https://VCENTER_PROD.EXAMPLE.COM:12443/vmwb/logbrowser: Host name may not be nullThis is an inherited issue, and to get the user name to successfully work in the 'Add Array' section, omit the underscore.Fore more information, please see this VMware KB.