code: private InternalServerErrorException apiFailure(String path, AuthleteApiException e)
      {
          // Error message.
          String message = String.format("Authlete %s API failed: %s", path, e.getMessage());
  
          // Response body in the response from the Authlete server.
          if (e.getResponseBody() != null)
          {
              // Append the content of the response body to the error message.
              message = new StringBuilder(message)
                      .append(": ").append(e.getResponseBody()).toString();
          }
  
          // 500 Internal Server Error
          return internalServerError(message, e);
      }
docs: Create an {@link InternalServerErrorException} instance to indicate
  that an Authlete API call failed.