Create a user with only crud flex-objects rights for contacts

I want to create a user which is only allowed to do crud activities for contacts in admin, nothing else.
In accounts I created a user with the permissions:

  • Login to site allowed
  • login to Admin allowed
  • Flex Objects and list allowed

I did not changed contacts.yaml.

When I login with the created user I get three items in admin: Dashboard, Flex Objects and Logout.
Selecting Flex Objects I see Contacts field with 0 (?) entries. When I select Contacts I get an error: Insufficient permissions for task list. I changed the authorize and permission fields in the contacts.yaml file if something changed. But I get the same error.
My question is what do I have to change in contacts.yaml or in the user defenition or set to get the user rights to only admin the flex Object Contacts?