@Override
    public UserContext updateUserContext(UserContext context,
            AuthenticatedUser authenticatedUser, Credentials credentials)
            throws GuacamoleException {

        // Ignore auth attempts if no auth provider could be loaded
        if (authProvider == null) {
            logger.warn("User data refresh attempt ignored because the "
                    + "relevant authentication provider could not be loaded. "
                    + "Please check for errors earlier in the logs.");
            return null;
        }

        // Delegate to underlying auth provider
        return authProvider.updateUserContext(context, authenticatedUser, credentials);
        
    }
Logs a warning that the authentication process will be entirely aborted
due to an internal error, advising the administrator to set the
"skip-if-unavailable" property if error encountered is expected and
should be tolerated.
guacamole/src/main/java/org/apache/guacamole/extension/AuthenticationProviderFacade.java