Errors

Status	Meaning	Common causes
`400`	Bad Request	A required field is missing, validation failed, an unknown key was sent to a strict endpoint, or an authorization code or refresh token is invalid, expired, or already used.
`401`	Unauthorized	The `Authorization` header is missing, or the access token is invalid or expired.
`403`	Forbidden	The user doesn’t have permission to access or change the resource.
`404`	Not Found	The resource doesn’t exist, or the user can’t access it.
`405`	Method Not Allowed	The request used a method other than `POST`.
`500`	Server Error	Something went wrong on Lunacal’s side. Retry with exponential backoff.

Status

Meaning

Common causes

400

Bad Request

A required field is missing, validation failed, an unknown key was sent to a strict endpoint, or an authorization code or refresh token is invalid, expired, or already used.

401

Unauthorized

The Authorization header is missing, or the access token is invalid or expired.

403

Forbidden

The user doesn’t have permission to access or change the resource.

404

Not Found

The resource doesn’t exist, or the user can’t access it.

405

Method Not Allowed

The request used a method other than POST.

500

Server Error

Something went wrong on Lunacal’s side. Retry with exponential backoff.

Handling errors

401 — Access token expired

Call /api/mcp/refresh to get a new token pair, then retry the original request once.

400 — Refresh token invalid

The refresh token has expired, was already used, or was revoked. Send the user through the authorization flow again.

400 — Unknown key on update

event-types/update uses a strict schema. Remove any fields not listed in its reference.

405 — Method not allowed

Every MCP endpoint accepts POST only, including read operations.

Event Types

Availability

Advanced

Teams & Workspaces

Bookings

Integrations

Workflows

Dynamic Bookings

Bookings Page

Embed

Others

Webhooks

Zapier

UTM Setup

Report Vulnerability

MCP API

Handling errors

​Handling errors

Handling errors