> ## Documentation Index
> Fetch the complete documentation index at: https://docs.junction.com/llms.txt
> Use this file to discover all available pages before exploring further.

# PSC Appointment Errors and Troubleshooting

> Handle slot conflicts, invalid requests, order-state errors, and provider failures when scheduling PSC appointments.

PSC appointment errors fall into four broad categories: unavailable slots, invalid input, an incompatible order state, or a provider failure. Handle errors according to whether the patient can retry, your integration must correct the request, or Junction support must review the order.

## Slot availability

Appointment availability can change between searching and booking. When a slot is no longer available, ask the patient to select another time and request fresh availability.

Sandbox and production can return different status codes for a slot conflict:

| Environment | Typical status | Behavior                                                             |
| ----------- | -------------- | -------------------------------------------------------------------- |
| Sandbox     | `400`          | The mock provider does not reproduce every production conflict.      |
| Production  | `404`          | The provider reports that the requested slot is no longer available. |

Handle both `400` and `404` as possible slot-unavailability responses when the message indicates a slot conflict.

| Example message                                                           | Recommended action                                           |
| ------------------------------------------------------------------------- | ------------------------------------------------------------ |
| `This appointment slot is no longer available. Please select a new time.` | Request fresh availability and select another slot.          |
| `No slots found for zip code`                                             | Try another date range, radius, or location.                 |
| `No slots found. Not all PSCs support scheduling...`                      | Select locations with `appointment_scheduling_via_junction`. |

## Invalid requests

| Example message                                             | Recommended action                                                |
| ----------------------------------------------------------- | ----------------------------------------------------------------- |
| `Invalid booking key format`                                | Request availability again and use the returned booking key.      |
| `Location with site code {code} not found`                  | Use a site code returned by PSC Info or appointment availability. |
| `Location with site code {code} is no longer active`        | Select another location.                                          |
| `start_date must be greater or equal than the current date` | Use the current date or a future date.                            |
| `site_codes or zip_code must be provided`                   | Provide site codes or a ZIP code.                                 |
| `radius must be provided when using zip_code`               | Include a search radius.                                          |
| `site_codes must be less than or equal to 3`                | Send no more than three site codes.                               |

Several invalid requests return `400`. If the response does not include a machine-readable error code, inspect the message to distinguish errors that require different corrective actions.

## Order-state errors

| Condition                                                                  | Recommended action                                                                                          |
| -------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------- |
| The order does not exist or belongs to another Team                        | Verify the order ID and API credentials.                                                                    |
| The order is not a walk-in order                                           | Use an order with the walk-in collection method.                                                            |
| The order does not have a requisition                                      | Wait for `requisition_created`, unless pre-requisition scheduling is enabled.                               |
| The order cannot be booked, rescheduled, or cancelled in its current state | Retrieve the current order and appointment before retrying. Contact support if the state appears incorrect. |
| The order's laboratory does not support Junction scheduling                | Let the patient walk in or schedule directly with the laboratory.                                           |

## Appointment-state errors

| Condition                                 | Recommended action                                                           |
| ----------------------------------------- | ---------------------------------------------------------------------------- |
| The order does not have an appointment    | Book an appointment before attempting to retrieve, reschedule, or cancel it. |
| `can_reschedule` is false                 | Cancel the appointment and book another slot when cancellation is allowed.   |
| The appointment is completed or cancelled | Do not retry the operation on that appointment.                              |
| The appointment was already cancelled     | Treat the desired cancellation state as satisfied.                           |

## Authentication and feature availability

| Status | Meaning                                        | Recommended action                       |
| ------ | ---------------------------------------------- | ---------------------------------------- |
| `401`  | The API key is missing or invalid.             | Verify the environment and Team API key. |
| `403`  | The Team cannot access the order or operation. | Verify ownership and Team configuration. |
| `503`  | PSC appointment scheduling is not enabled.     | Contact your Customer Success Manager.   |

## Testing error handling

* Use sandbox to test validation and incompatible-order scenarios.
* Do not rely on sandbox to reproduce every real-time slot conflict.
* In production, do not create speculative appointments solely to test failure handling.
* Always fetch fresh availability after a slot conflict.

If an order remains in an unexpected state after you retrieve its current order and appointment records, [contact Junction support](/home/getting-support).