Cannot make a change to a subscription that generates a credit for a transaction that is currently being processed

You can't make a change to a subscription that generates a credit for a transaction that is currently being processed.

Error Message	`The subscription update you're trying to make generates a credit for a transaction that is currently being processed.`
Error Code	`subscription_credit_creation_against_processing_transaction`
Status Code	`400`

Common causes

You're trying to make a change to a subscription that generates a credit for a transaction that is currently being processed. This can sometimes happen if you make a change immediately after a subscription is created or renewed, or make two subscription updates one after the other.

Solutions

Wait a few moments until the related transaction is completed, then try again.
If you don't need to create a credit for this change, send your request with do_not_bill as the proration billing mode.