Best way to restrict page access?

I’m designing a website with a form component that redirects to a “failure” or “success” component based on whether the form submits without an error or not. Here is the code I’m using:

                  await axios.post('/api/patients/', data, axiosConfig)
                  .then((response) => {
                    history.push('/success')
                  })
                  .catch((error) => {
                    history.push('/failure')
                  })

This works well even when I intentionally make a bad request by turning my network off or changing the route. However, I can type in the “/success” route in my browser and access it whether or not I’ve submitted the form. How do I restrict this behavior?