Create of find portal-only customers from ServiceDeskApi

[Marveri Jira Administrator]

Hi

I noticed that searching a customer who did not signed up by his email address will result in an empty list.
Route: /rest/servicedeskapi/servicedesk/1/customer?query=EMAIL

If I try to create it, I have got an error : email already exists. Indeed, he's been created before.

NB: I also tried to search for users, and it's an empty list as well.
Route: /rest/api/3/user/search?query=EMAIL

Does someone know how am I supposed to retrieve a "pending" customer / a customer who hasn't signed up yet ? I need its accountId.

NB2: I can see my pending customers in the JIRA admin / site / Portal-only customers.

Many thanks