I'm using the PHP SDK to update subscriptions and get error code E00013: Start Date cannot be changed. The only limitation per the docs (https://developer.authorize.net/api/reference/#recurring-billing-update-a-subscription) is that the start date can't be prior to the created date. I'm definitely not doing that. What am I missing? Or how do I work around this?
You may use the support article found here to understand what is and is not possible once a subscription has been created.
The first bullet point advises that the start date cannot be modified within an active subscription, which is what your error indicates you are attempting to do. ]
I hope this information is helpful.
Thanks. I came to the same conclusion.
I ended up creating a tool that will cancel the existing sub and create a new one based on the existing customer info, and with the desired new start date. Wish I didn't have to cancel/create -- but it gets the job done.