I have a client that is trying to make it so that a specific type of subscription order customer gets a free month. To do so, we need to change the re-bill date on that subscription +1mo
When trying to update the subscription for the customer, I keep getting a 400 error and cannot figure out why.


This shows me manually trying to put in a date. I have tried different date formats as well. Ive tried pulling the order date and doing +1y, +1mo
Even when I leave the date blank im getting the 400 error