Sandbox: CheckoutApi redirect_url occasionally gives 'whoops 404'

Sandbox: When using the checkoutApi and Paying for the order, the expected behaviour is a redirect to the specified redirect_url.
On occasion (Generally after 8:00 PM pst onwards) this gives a ‘whoops 404’ not found. It seems to clear up sometime late next morning.
When it gives the 404, manually accessing the redirect_url, shows that it is accessible.
Is this sandbox feature temporarily down at this time? How can we figure out what happened? Appreciate all replies

:wave: Do you have an example checkout that you got this error with?

Thank you for responding. It is not consistent (except that around 8:00PM pst, it starts happening and clears up next day. Will send the next one if it occurs. Thx - Vasan