Cannot resume subscription without payment method

You're trying to resume an automatically-collected subscription, but it doesn't have a payment method.

Error Message	`Automatically-collected subscriptions require a payment method to be resumed immediately.`
Error Code	`subscription_missing_payment_method_cannot_resume`
Status Code	`400`

Common causes

The subscription doesn't have a payment method set, so it can't be resumed immediately.
If the customer_id against this subscription has been replaced recently, the payment method against it was removed for security. It must be readded.

Solutions

Create a customer portal session to capture a payment method from the customer, then try resuming again.
Get a transaction to update payment method and pass to Paddle.js to capture a payment method from the customer, then resume again.
Change collection mode against the subscription to manual, then retry the resume. Paddle sends an invoice for the amount due each time a subscription renews or a charge is made.