Moodle core_user_create_users Access control exception

Can anyone tell me how to use the example code here ? 

https://github.com/moodlehq/sample-ws-clients/blob/master/JAVA-REST/RestJsonMoodleClient.java

When I use my admin token from manage token, it always give:

{"exception":"webservice_access_exception","errorcode":"accessexception","message":"Access control exception"}

The tutorials I found did not solve the problem. I currently use moodle cloud.

Thanks in advance