When requests to Step Function fail, Workflow Service performs exponential backoff retries to notify Step Function service. Number of retries = 3 The total duration of all attempts doesn't exceed 10 seconds, the processing must not exceed the message visibility timeout.

@Override
public void 
  handle(WorkflowExecutionEvent event, 
  Error error, 
  StepFunctionRetryer retryer) {
  // The processing must not exceed the message visibility timeout
  if (System.currentTimeMillis() < event.getMessage().getExpectedExecutionTimeInSeconds() * 1000) {
    try {
      retryer.retry(event, error);
    } catch (Exception e) {
      // This exception is thrown if the maximum number of retries has been exhausted.
      // At this point we can decide to fail the step function execution or to retry the execution again.
      // We can also use the retryer.retry(event, error, delayInSeconds) method to control the delay for the next retry.
      // The delays are calculated using an exponential backoff algorithm.
      retryer.retry(event, error);
    }
  }
}