code: private void warnAuthAborted() {
          String identifier = getIdentifier();
          logger.warn("The \"{}\" authentication provider has encountered an "
                  + "internal error which will halt the authentication "
                  + "process. If this is unexpected or you are the developer of "
                  + "this authentication provider, you may wish to enable "
                  + "debug-level logging. If this is expected and you wish to "
                  + "ignore such failures in the future, please set \"{}: {}\" "
                  + "within your guacamole.properties.",
                  identifier, ExtensionModule.SKIP_IF_UNAVAILABLE.getName(),
                  identifier);
      }
docs: 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.