# Session Expired

Indicates checkout session has reached its expiration point. Initiate a new checkout.

## Common Causes

- The checkout reached its expiration time before payment completed.
- The customer attempted to pay after the checkout TTL elapsed.
- A delayed payment method completed after expiration.

```json
{
  "type": "https://developer.sumup.com/problem/session-expired",
  "title": "Conflict",
  "status": 409,
  "detail": "The checkout session ae98b9cc-2287-4621-afa1-d36ae2ea219d is already processed",
  "instance": "1bfe72b34387"
}
```