Can't activate a trialing subscription without a payment method

{
  "error": {
    "type": "request_error",
    "code": "subscription_missing_payment_method_cannot_activate",
    "detail": "Automatically-collected subscriptions in trial require a payment method to be activated.",
    "documentation_url": "https://developer.paddle.com/errors/subscriptions/subscription_missing_payment_method_cannot_activate"
  },
  "meta": {
    "request_id": "00000000-0000-0000-0000-000000000000"
  }
}

Details

Status code

400

Error code

subscription_missing_payment_method_cannot_activate

Error message

Automatically-collected subscriptions in trial require a payment method to be activated.

Common causes

• The trialing subscription doesn't have a payment method, so it can't become active.
• If the customer_id on this subscription was replaced recently, the payment method was removed for security and must be readded.

Troubleshooting

• Create a customer portal session to capture a payment method from the customer, then retry the activation.
• Get a transaction to update payment method and pass it to Paddle.js to capture a payment method, then retry the activation.
• Change the subscription's collection_mode to manual, then retry. Paddle sends an invoice for the amount due on each renewal or charge.