BeLaBu,
Are you including the API key in your headers? Make sure you include the API key in the header "X-DreamFactory-Api-Key" and also double check to ensure permissions are properly assigned.
"http://{yourinstance}.com/test_rest" is a great way to test to make sure that a) roles are properly assigned and b) that the API key is infact working. You'll have to create a new app within your platform in order to receive an API key.
