Unable to use after enabling Kibana user management

Hi, Vera
Thanks for your reply. I've tried all the parameters related with Timeout in kibana.yml but still not working.
The error message is:
http://localhost:5601/login?next=%2Fapp%2Fflexmonster_pivot&msg=SESSION_EXPIRED#?_g=()
Since Flexmonster works fine before I enable user management, I think there's something related with it. 
After I clicked the Flexmonster icon, several windows flashed and then I went back to the login UI with session timeout message. 
I want to attach my yml files but seems it's not allowed. I'll just paste the content here.
Elasticsearch.yml:
http.cors.enabled : true
http.cors.allow-origin : "*"
http.cors.allow-credentials: true
http.cors.allow-methods : OPTIONS, HEAD, GET, POST, PUT, DELETE
http.cors.allow-headers : kbn-version, Origin, X-Requested-With, Content-Type, Accept, Engaged-Auth-Token, Content-Length, Authorization
xpack.security.enabled: true
discovery.type: single-node
 
Kibana.yml:
elasticsearch.hosts: ["http://localhost:9200"]
server.cors: true
server.cors.origin: ['*']
kibana.index: ".kibana"
elasticsearch.username: "kibana"
elasticsearch.password: "kibana"
elasticsearch.pingTimeout: 600000
elasticsearch.requestTimeout: 600000
elasticsearch.shardTimeout: 600000
elasticsearch.startupTimeout: 600000
xpack.security.sessionTimeout: 600000