code: void sendDisplayError(HttpServletResponse response, String msgKey, Object... args) throws IOException {
          if (msgKey == null) {
              if (tc.isDebugEnabled()) {
                  Tr.debug(tc, "No message key was provided for sub-message, so no sub-message will be included");
              }
              msgKey = "";
          }
          String subMsg = Tr.formatMessage(tc, msgKey, args);
          Tr.error(tc, "ERROR_DISPLAYING_SIGN_IN_PAGE", subMsg);
          ErrorHandlerImpl.getInstance().handleErrorResponse(response);
      }
docs: Traces that there was an error displaying the sign in page, and includes the provided NLS message information to include as
  an insert (e.g. Will output "CWWKSxxxxE: The default social media sign in page cannot be displayed. {0}", where {0} is
  replaced with the properly formatted NLS message using the {@code msgKey} and {@code args} provided). Then redirects the
  response to an error page with a generic front-end failure message.
  
  @param response
  @param msgKey
  @param args
  @throws IOException