This error message is returned in API responses when the API request involves a product (tour, service, class) that is not bookable by customers.
By default all products in a connected account are visible to customers.
However an account manager can change the visibility of a product to "only I and authorized users", meaning that customers cannot view or book the product. This is done in the "General" tab of the product settings page, in the section "Visibility".
An application using the Bookeo API can and should invoke GET /settings/products to find out which products are visible to customers. This is included in the response, where each returned product has a property shownToCustomers .
Applications should not query the availability or try and create bookings for products on behalf of customers where shownToCustomers is false.
By default, Bookeo treats an application as if acting on behalf of customers - this is the most restrictive assumption. However an application can act on behalf of users (i.e. staff of the business), by adding the query string parameter mode=backend to the request URL (where it makes sense and where allowed - see the API reference for details). When the request uses this parameter, the application informs Bookeo it is acting on behalf of an account user instead of a regular customer, and so availability will be shown and bookings will be possible.
An application should only use the mode=backend parameter with the permission of the account owner, or where the application purpose is clearly meant to operate on behalf of users and not of customers.