Can not add User RestApi Plugin v1.8.2

I have installed Openfire latest version 4.7.1 on my local computer (windows 10-> Ip:10.20.4.20). I have installed rest api to the plugins(1.8.2), but I am requesting to add users with postman. When I make a request, response 404 Not Found. When I examine the log file, I get the following error…

POSTMAN : **POST** http://10.20.4.20:9090/plugins/restapi/v1/users
HEADERS: Authorization :network_timeout
CONTENT TYPE: application/json
BODY :{"username": "test6", "password": "test6"}
-----
' DEBUG [Jetty-QTP-AdminConsole-197]: org.jivesoftware.util.WebManager - Unable to get user: no session or no auth token on session.'

Can you help with this? Thank you.

That does not seem to be a proper value (unless you made your shared secret be :network_timeout, which is a strange password).