The property wt.auth.trustedHosts defines hosts that are allowed to communicate Windchill, e.g distributed cognos installation, Visualization worker.... Currently, the given hosts are only evaluated during run-time, e.g when a Cognos report is run. When the hostname of any of the given hosts in this property can not be resolved to an IP address, access to Windchill will be denied for any other host mentioned in the property.
To avoid trail-and-error for simple errors, like typos, it would be helpful, if this property is evaluated during property propagation (xconfmanager -p) or windchill start-up, and print a warning if one of the hosts cannot be resolved. That way, one could correct the error even before Windchill is fully started.