Create Contact failed with Permission error only for one User

Hi,
we implemented an App that enable Users to create contacts and organisations in Pipedrive via API. But we do have one User who fails to do so, we are getting the error response from the API -Permission denied.
The first feedback from the tech team was that the new item is not set to be visible to that user. But we are setting the current user as the owner ID of the new contact. How can the new item not be visible to its owner?
We only have this problem with one of our users, is there a special Setting in Pipedrive we can ask them to check?

Appreciate your help!